I made this because the lego lattice inserts (3273 / 38320) that are included with the 71436 Boo's Haunted Mansion playset barely stay in the windows and frequently fall out by being touched. I reverse engineered them & made them .5mm longer to fit nice and snug within the frames. I've also made them with a bowser's face inside for a fun spin on the window insert. (lego please hire me)