Exhibit 3.31

                            CERTIFICATE OF INCORPORATION

                                         OF

                                     HEAT, INC.


                                    ARTICLE ONE

          The name of the corporation is Heat, Inc.

                                    ARTICLE TWO

          The address of the corporation's registered office in the State of
Delaware is 1013 Centre Road, in the City of Wilmington, County of New Castle,
19805.  The name of its registered agent at such address is Corporation Service
Company.

                                   ARTICLE THREE

          The nature of the business or purposes to be conducted or promoted is
to engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of the State of Delaware.

                                    ARTICLE FOUR

          The total number of stock which the corporation has authority to issue
is one thousand (1,000) shares of Common Stock, par value one cent ($0.01) per
share.

                                    ARTICLE FIVE

          The name and mailing address of the sole incorporator are as follows:

          NAME                MAILING ADDRESS
          -----------------   -----------------------------
          Thaddine G. Gomez   200 East Randolph Drive
                              Suite 5700
                              Chicago, Illinois 60601

                                    ARTICLE SIX

          The corporation is to have perpetual existence.




                                   ARTICLE SEVEN

          In furtherance and not in limitation of the powers conferred by
statute, the board of directors of the corporation is expressly authorized to
make, alter or repeal the by-laws of the corporation.

                                   ARTICLE EIGHT

          Meetings of stockholders may be held within or without the State of
Delaware, as the by-laws of the corporation may provide.  The books of the
corporation may be kept outside the State of Delaware at such place or places
as may be designated from time to time by the board of directors or in the
by-laws of the corporation.  Election of directors need not be by written
unless the by-laws of the corporation so provide.

                                    ARTICLE NINE

          To the fullest extent permitted by the General Corporation Law of the
State of Delaware as the same exists or may hereafter be amended, a director of
this corporation shall not be liable to the corporation or its stockholders for
monetary damages for a breach of fiduciary duty as a director.  Any repeal or
modification of this ARTICLE NINE shall not adversely affect any right or
protection of a director of the corporation existing at the time of such repeal
or modification.

                                    ARTICLE TEN

          The corporation expressly elects not to be governed by Section 203 of
the General Corporation Law of the State of Delaware.

                                   ARTICLE ELEVEN

          The corporation reserves the right to amend, alter, change or repeal
any provision contained in this certificate of incorporation in the manner now
or hereafter prescribed herein and by the laws of the State of Delaware, and all
rights conferred upon stockholders herein are granted subject to this
reservation.

          I, THE UNDERSIGNED, being the sole incorporator hereinbefore named,
for the purpose of forming a corporation pursuant to the General Corporation Law
of the State of Delaware, do make this certificate, hereby declaring and
certifying that this is my act and deed and the facts stated herein are true,
and accordingly have hereunto set my hand on the 2nd day of January, 1997.



                                         /s/ Thaddine G. Gomez
                                         ------------------------------
                                         Thaddine G. Gomez
                                         Sole Incorporator



                                      2



                            CERTIFICATE OF AMENDMENT

                                     TO THE

                          CERTIFICATE OF INCORPORATION

                            BEFORE PAYMENT OF CAPITAL

                                       OF

                                   HEAT, INC.

                                   * * * * *

        ADOPTED IN ACCORDANCE WITH THE PROVISIONS OF SECTION.241(b) OF THE
                         GENERAL CORPORATION LAW OF THE
                                STATE OF DELAWARE
                                    * * * * *

                The undersigned, being the President of Heat, Inc., a
corporation duly organized and existing under and by virtue of the laws of the
State of Delaware (the "Corporation"), does hereby certify as follows:

                FIRST:   The Certificate of Incorporation of the Corporation
(the "Certificate of Incorporation") is hereby amended by deleting ARTICLE
FOUR in its entirety and substituting therefor a new ARTICLE FOUR as set
forth on Exhibit A attached hereto and made a part hereof.

                SECOND:  The Corporation has not received payment for any of
its stock.

                THIRD:   The foregoing amendment has been duly adopted,
pursuant to the provisions of Section 241(b) of the General Corporation Law
of the State of Delaware, by the sole incorporator of the Corporation.


                IN WITNESS WHEREOF, the undersigned, being the President of the




Corporation, for the purpose of amending the Certificate of Incorporation of
the Corporation pursuant to the General Corporation Law of the State of
Delaware, under penalties of perjury does hereby declare and certify that
this is the act and deed of the Corporation and the facts stated herein are
true, and accordingly has hereunto signed this Certificate of Amendment
Before of Payment Capital to the Certificate of Incorporation as of the 29th
Day of May, 1997.

                                         Heat, Inc.,

                                         a Delaware corporation


                                         By:  /s/ BRIAN D. SCHWARTZ
                                            ----------------------------------
                                            Brian D. Schwartz
                                            President


                                        2



                                                                       EXHIBIT A

                                  ARTICLE FOUR


                  The corporation shall have authority to issue 6,000,000 shares
consisting of 5,000,000 shares of Class A Common Stock par value $0.01 per share
("Class A Common Stock") and 1,000,000 shares of Class B Common Stock, par value
$0.01 per share sometimes collectively referred to herein as the "Common Stock."

                  The designations and the powers, preferences and rights of the
Class A Common Stock and Class B Common Stock are as follows:

                  (a) VOTING RIGHTS. (1) The holders of the Class A Common Stock
shall be entitled to vote on each matter on which the stockholders of the
Corporation shall be entitled to vote, and each holder of Class A Common Stock
shall be entitled to one vote for each share of such stock held by such holder.

                  (2) The holders of Class B Common Stock shall not have any
voting rights, except as otherwise required by applicable law, in which case
holders of Class B Common shall vote (at the rate of one vote per share of Class
B Common Stock held) as a single class of such matter unless otherwise required
by law.

                  (b) DIVIDENDS. The Board of Directors of the Corporation may
cause dividends to be paid to the holders of shares of Common Stock out of funds
legally available for the payment of dividends or other distributions (including
without limitations any grant or distribution of rights to subscribe for or
purchase shares of capital stock or securities or indebtedness convertible into
capital stock of the Corporation) are declared, whether payable in cash, in
property or in shares of stock of the Corporation, other than shares of Class A
Common Stock or Class B Common Stock, the holders of Class A Common Stock and
Class B Common Stock shall be entitled to share equally, share for share, in
such dividends or other distributions as if all such shares were of a single
class. No dividends or other distributions shall be declared or paid in shares
of Class A Common securities convertible into or exchangeable for shares of
Common Stock held by them, in shares of Class A Common Stock to holders of that
class of stock and Class B Common Stock to holders of that class of stock.

                  (c) LIQUIDATION RIGHTS. In the event of any voluntary or
involuntary liquidation, dissolution or winding up of the affairs of the
Corporation holders of Common Stock shall be entitled t share ratably
according to the number of shares of Common Stock held by them, in all assets of
the Corporation available for distribution to its stockholders.


                                        1


                  (d) CONVERSION. (1) Each share of Class B Common Stock shall
be convertible into one share of Class A Common Stock, at any time and from time
to time, upon delivery to the Corporation of a Certificate, signed by or on
behalf of the holders seeking such conversion, to the effect that such
conversion and the holding of such Class A Common Stock by such holder or
holders are permitted under the then current applicable law, in form and
substance reasonably acceptable to the Corporation. Any conversion of shares of
Class B Common Stock into shares of Class A Common Stock pursuant to this Clause
(d)(1) shall be effected by the delivery to the Corporation at its principal
executive office of the certificates representing shares to be converted, duly
endorsed, together with written instructions that the shares are to be
converted, and accompanied by the required certificate described herein.

                  (2) Each share Class A Common Stock shall be convertible into
one share of Class B Common Stock at any time and from time to time, at the
options of the holder thereof. Any conversion of shares of Class A Common Stock
into shares of Class B common Stock pursuant to this Clause (d)(2) shall be
effected by the delivery to the Corporation at its principal executive office of
the certificates representing shares to be converted, duly endorsed, together
with written instructions that the shares are to be converted.

                  (3) The Corporation shall at all times reserve and keep
available out of its authorized but unissued Common Stock, solely for the
purpose of effecting conversions pursuant to this ARTICLE FOUR, the full number
of shares of Common Stock of each class from time to time issuable upon the
Conversion of all shares of Common Stock then outstanding and entitled to
convert, and shall take all such action and obtain all such permits or orders as
may be necessary to enable the corporation lawfully to issue such shares upon
any such conversion. In addition, the Corporation shall also reserve and keep
available other such securities and property as may from time to time be
deliverable upon conversion on Common Stock and shall take all such action and
obtain all such permits or orders as may be necessary to enable the Corporation
lawfully to deliver such other securities and property upon conversion. So long
as any shares of Common Stock shall be outstanding, the Corporation will take
all corporate action necessary in order that the Corporation may validly and
legally issue full paid and nonassessable shares of Common Stock upon any
conversion thereof.

                  (e) SUBDIVISIONS AND COMBINATIONS. If shares of either class
of Common Stock are subdivided or combined, then shares of both classes of
Common Stock shall be so subdivided or combined.

                  (f) REGULATED STOCKHOLDERS.  The Corporation will not
convert or directly or indirectly redeem, purchase, acquire or take any other
actions affecting the percentage of outstanding voting securities owned or
controlled by any Regulations Y Holder and its Affiliates (other than a
Regulation Y Holder which waives in writing its

                                      2


rights under this ARTICLE FOUR) unless the Corporation gives written notice
(the "Deferral Notice") of such actions to each Regulation Y Holder. The
Corporation will defer making any such conversion, redemption, purchase or
other acquisition, or taking any such other action, for a period or 20 days
(the "Deferral Period") after giving the Deferral Notice in order to allow
each Regulation Y Holder to determine whether it wishes to convert or take
any other action with respect to the Common Stock it owns, controls or has
the power to vote, and if any Regulation Y Holder then elects to convert any
shares of Class A Common Stock, it shall notify the Corporation in writing
within 10 days of the issuance of the Deferral Notice in which case the
Corporation shall promptly notify from time to time prior to the end of such
20-day period each other Regulation Y Holder of each proposed conversion and
effect the conversions requested by all Regulation Y Holders at the end of
the Deferral Period. The Corporation will not directly or indirectly redeem
purchase, acquire or take any other action affecting outstanding shares of
Common Stock of the Corporation if such action wiII increase over 24.9% the
percentage of outstanding Common Stock owned or controlled by any Regulation
Y Holder and its Affiliates (other than a Regulation Y Holder which waives in
writing its rights under this ARTICLE FOUR).

                (g) DEFINED TERMS. As used in this ARTICLE FOUR, the following
terms shall have the meanings shown below:

                1. "AFFILIATE" shall mean, with respect to any Person, any other
Person directly or indirectly controlling, controlled by or under common control
with such Person. For the purpose of the above definition, the term "control"
(including with correlative meaning, the terms "controlling," "controlled by"
and "under common control with"), as used with respect to any Person, shall mean
the possession, directly or indirectly, of the power to direct or cause the
direction of the management and policies of such Person, whether through the
ownership of voting securities or by contact otherwise.

                2. "REGULATION Y HOLDER" shall mean any stockholder of the
Corporation that is a bank holding company within ft meaning of the Bank Holding
Company Act of 1956, as amended, or a subsidiary thereof subject to Regulation Y
under such Act.

                                        3


                            CERTIFICATE OF CORRECTION
                                       TO
                            CERTIFICATE OF AMENDMENT
                                       TO
                          CERTIFICATE OF INCORPORATION
                                       OF
                                   HEAT, INC.
                                    * * * *

        ADOPTED IN ACCORDANCE WITH THE PROVISIONS OF SECTION.103(f) OF THE
                GENERAL CORPORATION LAW OF THE STATE OF DELAWARE
                                    * * * *

                Brian D. Schwartz, being the President of Heat, Inc., a
corporation duly organized and existing under and by virtue of the General
Corporation Law of the State of Delaware (the "Corporation"), DOES HEREBY
CERTIFY as follows:

                FIRST:   The name of the corporation is Heat Inc. (the
"Corporation").

                SECOND:  The section entitled (b) DIVIDENDS and the section
entitled (f) REGULATED STOCKHOLDERS of the Certificate of Amendment to the
Certificate of Incorporation of the Corporation (the "Certificate of Amendment")
which was filed with the Secretary of State of Delaware on May 29, 1997
erroneously stated the intention of the Board of Directors and such sections are
hereby corrected.

                THIRD:   The Exhibit A to the Certificate of Amendment
containing the erroneous sections in its corrected form is as set forth of
Exhibit A attached hereto.




                IN WITNESS WHEREOF, the undersigned, being the President
hereinabove named, for the purpose of correcting the Certificate of Amendment
pursuant to the General Corporation Law of the State of Delaware, under the
penalties of perjury does hereby declare and certify that this is the act and
deed of the Corporation and the facts stated herein are true, and accordingly
has hereunto signed this Certificate of Correction to the Certificate of
Amendment this 30th day of May, 1997.

                                           Heat Inc.,
                                           a Delaware corporation



                                           By:   /s/ BRIAN D. SCHWARTZ
                                               -------------------------------
                                                 Brian D. Schwartz
                                                 President


                                       -2-



                                                                       EXHIBIT A

                                  ARTICLE FOUR

                The corporation shall have authority to issue 6,000,000 shares
consisting of 5,000,000 shares of Class A Common Stock, par value $0.01 per
share ("Class A Common Stock") and 1,000,000 shares of Class B Common Stock, par
value $0.01 per share sometimes collectively referred to herein as the "Common
Stock."

                The designations and the powers preferences and rights of the
Class A Common Stock and Class B Common Stock are as follows:

                (a) VOTING RIGHTS. (1) The holders of the Class A Common Stock
shall be entitled to vote on each matter on which the stockholders of the
Corporation shall be entitled to vote, and each holder of Class A Common Stock
shall be entitled to one vote for each share of such stock held by such holder.

                (2) The holders of Class B Common Stock shall not have any
voting rights, except as otherwise required by applicable law, in which case
holders of Class B Common Stock shall vote (at the rate of one vote per share of
Class B Common Stock held) as a single class on such matter unless otherwise
required by law.

                (b) DIVIDENDS. The Board of Directors of the Corporation may
cause dividends to be paid to the holders of shares of Common Stock out of
funds legally available for the payment of dividends by declaring an amount
per share as a dividend. When and as dividends or other distributions,
(including without limitations any grant or distribution of rights to
subscribe for or purchase shares of capital stock or securities or
indebtedness convertible into capital stock of the Corporation) are declared,
whether payable in cash, in property or in shares of stock of the
Corporation, other than shares of Class A Common Stock or Class B Common
Stock, the holders of Class A Common Stock and Class B Common Stock shall be
entitled to share equally, share for share, in such dividends or other
distributions as if all such shares were of a single class. No dividends or
other distributions shall be declared or paid in shares of Class A Common
Stock or Class B Common Stock or options, warrants or rights to acquire such
stock or securities convertible into or exchangeable for shares of such
stock, except dividends or other distributions payable to all of the holders
of Common Stock held by them, in shares of Class A Common Stock to holders of
that class of stock and Class B Common Stock to holders of that class of
stock.

                (c) LIQUIDATION RIGHTS. In the event of any voluntary or
involuntary

                                     -3-


liquidation, dissolution or winding up of the affairs of the Corporation
holders of Common Stock shall be entitled t share ratably according to the
number of shares of Common Stock held by them, in all assets of the
Corporation of the Corporation available for distribution to its stockholders

                (d) CONVERSION. (1) Each share of Class B Common Stock shall be
convertible into one share of Class A Common Stock, at any time and from time to
time, upon delivery to the Corporation of a certificate, signed by or on behalf
of the holder or holders seeking such conversion, to the effect that such
conversion and the holding of such Class A Common Stock by such holder or
holders are permitted under the then current applicable law, in form and
substance reasonably acceptable to the Corporation. Any conversion of shares of
Class B Common Stock into shares of Class A Common Stock pursuant to this Clause
(d)(1) shall be effected by the delivery to the Corporation at its principal
executive office of the certificates representing shares to be converted, duly
endorsed, together with written instructions that the shares are to be
converted, and accompanied by the required certificate described herein.

                (2) Each share of Class A Common Stock shall be convertible into
one share of Class B Common Stock, at any time and from time to time, at the
options of the holder thereof. Any conversion of shares of Class A Common Stock
into shares of Class B Common Stock pursuant to this Clause (d)(2) shall be
effected by the delivery to the Corporation at its principal executive office of
the certificates representing shares to be converted, duly endorsed, together
with written instructions that the shares are to be converted.

                (3) The Corporation shall at all times reserve and keep
available out of its authorized but unissued Common Stock, solely for the
purpose of effecting conversions pursuant to this ARTICLE FOUR, the full
number of shares of Common Stock of each class from time to time issuable
upon the conversion of all shares of Common Stock then outstanding and
entitled to convert, and shall take all such action and obtain all such
permits or orders as may be necessary to enable the corporation lawfully to
issue such shares upon any such conversion. In addition, the Corporation
shall also reserve and keep available such other securities and property as
may from time to time be deliverable upon conversion on Common Stock and
shall take all such action and obtain all such permits or orders as may be
necessary to enable the Corporation lawfully to deliver such other securities
and property upon conversion. So long as any shares of Common Stock shall be
outstanding, the Corporation will take all corporate action necessary in
order that the Corporation may validly and legally issue full paid and
nonassessable shares of Common Stock upon any conversion thereof.

                (e) SUBDIVISIONS AND COMBINATIONS. If shares of either class of
Common Stock are subdivided or combined, then shares of both classes of Common
Stock shall be so subdivided or combined.

                (f) REGULATED STOCKHOLDERS. The Corporation will not convert
or directly or

                                     -4-


indirectly redeem, purchase, acquire or take any other actions
affecting outstanding shares of capital stock of the Corporation if such
action will increase the percentage of outstanding voting securities owned or
controlled by any Regulations Y Holder and its Affiliates (other than a
Regulation Y Holder which waives in writing its rights under this ARTICLE
FOUR), unless the Corporation gives written notice (the "Deferral Notice") of
such actions to each Regulation Y Holder. The Corporation will defer making
any such conversion, redemption, purchase or other acquisition, or taking any
such other action, for a period of 20 days (the "Deferral Period") after
giving the Deferral Notice in order to allow each Regulation Y Holder to
determine whether it wishes to convert or take any other action with respect
to the Common Stock it owns, controls or has the power to vote, and if any
regulation Y Holder then elects to convert any shares of Class A Common
Stock, it shall notify the Corporation in writing within 10 days of the
issuance of the Deferral Notice, in which case the Corporation shall promptly
notify from time to time prior to the end of such 20-day period each other
Regulation Y Holder of each proposed conversion and effect the conversions
requested by all Regulation Y Holders at the end of the Deferral Period. The
Corporation will not directly or indirectly redeem, purchase, acquire or take
any other action affecting outstanding shares of Common Stock of the
Corporation if such action will increase over 24.9% the percentage of
outstanding Common Stock owned or controlled by any Regulation Y Holder and
its Affiliates (other than a Regulation Y Holder which waives in writing its
rights under the ARTICLE FOUR).

                (g) DEFINED TERMS. As used in this ARTICLE FOUR, the following
terms shall have the meanings shown below:

                1.  "AFFILIATE" shall mean, with respect to any Person, any
other Person directly or indirectly controlling, controlled by or under
common control with such Person.  For the purpose of the above definition,
the term "control" (including with correlative meaning, the terms
"controlling," "controlled by" and "under common control with"), as used with
respect to any Person, shall mean the possession, directly or indirectly, of
the power to direct or cause the direction of the management and policies of
such Person, whether through the ownership of voting securities or by contact
otherwise.

                2. "REGULATION Y HOLDER" shall mean any stockholder of the
Corporation that is a bank holding company within the meaning of the Bank
Holding Company Act of 1956, as amended, or a subsidiary thereof subject to
Regulation Y under such Act.

                                       -5-