X0205 3 2012-04-24 0 0001434524 CLEARSIGN COMBUSTION CORP CLIR 0000897744 MARLETT CHRISTOPHER A 401 WILSHIRE BLVD. SANTA MONICA CA 90401 0 0 1 0 Common Stock 74573 D Common Stock 454545 I See Footnote Common Stock 289207 I See Footnote Common Stock Warrants 2.20 2011-05-10 2016-05-10 Common Stock 17409 D Common Stock Warrants 2.20 2011-05-10 2016-05-10 Common Stock 74318 I See Footnote Common Stock Warrants 5.00 2013-04-24 2017-04-24 Common Stock 300000 I See Footnote The record holder of these securities is Integrated Surgical Systems, Inc. ("ISS"). The reporting person is the Chief Executive Officer and a director of ISS. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities in this report shall not be an admission of beneficial ownership of all of the reported securities for purposes of Section 16 or for any other purpose. The record holder of these securities is MDB Capital Group LLC ("MDB"). The reporting person is the Chief Executive Officer of MDB. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities in this report shall not be an admission of beneficial ownership of all of the reported securities for purposes of Section 16 or for any other purpose. /s/ Christopher Marlett 2012-04-30