It's a bed level test in the shape of the transmutation circle used for human transmutation in Fullmetal Alchemist, plus a large square around the test area. I just thought it'd be fun to see the printer draw it. It's exactly 200mm x 200mm which is a generic smaller Prusa table size ( I have a 220x220 mm mk 3 table), bur you should shrink it in your slicer a bit, especially if you have an additional surface that is attached with some kind of clamps, like aglass or wood panel, so the head doesn't bump into them or doesn't draw outside the table. It prints in about 20 minutes at 95% size if brim is disabled and at 30mm/s with old Cura and Anet a6 printer. It contains symbols, circles and both fat and thin lines so it gives a good enough idea if the bed is level enough as well as whether the printer draws circles correctly and has its beginning and ending of table accurately corresponding to where the actual table is, which is important if printing a big item or a lot of things at a time. I added one with more material on corners now.