Tetris “L” block. One of five to mix and match. 

Each shape is made in 3 sizes…. 30mm, 45mm, and 60mm. I strongly recommend not changing the size in XCS since 3mm plywood was used in the designing of each shape. If you change the size of the design, the pieces will not fit correctly. That is the reason I made 3 separate sizes.  Each size is in a different canvas along with a canvas showing the 3 different sizes. Also note that some of the pieces are very similar in size. So if the pieces don’t fit right you are probably trying to fit a wrong piece.