OpenSCAD and STL files for solids with given shadows from top, side and front.
Carpeted Hexaflake: Hexagon, Koch snowflake, Sierpinski carpet. Read more at https://samhartburn.co.uk/sh/the-carpeted-hexaflake/. CarpetedHexaflake_Snow2Carpet2_print.stl has a flat base for printing - print two and glue them together.
CircleTriangleSquare: Circle, Triangle, Square. Created from two cones. See https://twitter.com/alytile/status/1031156066120228866 and https://twitter.com/panlepan/status/1296043526745141250 CircleTriangleSquare_Full.stl is the full shape. CircleTriangleSquare_ToPrint.stl has a flat base for printing - print two and glue them together.