Seen any images floating around of the new building Houston’s Museum of Fine Arts is planning for the northwest corner of the Bissonnet and South Main, next to the Cullen Sculpture Garden? Well then, this watercolor-and-charcoal “concept sketch” for the building by architect Steven Holl from a year and a month ago may interest you. It’s going up for auction tomorrow — as part of a fundraiser for the nonprofit Architecture for Humanity. Holl was selected from a group of 3 finalists this past February, beating out LA design firm Morphosis and Oslo’s Snøhetta for the MFAH commission of a new structure to house 20th- and 21st-century art.