Test your printer's X-Y accuracy with this little puzzle. Each connection has a different clearance, as indicated by the numbers (0.15mm,0.2mm,0.3mm,0.4mm).

I made this to help design my 3D puzzles, but it's useful for designing any parts that fit together. Is your printer able to connect them all?

Ideally, the 0.15 connection will be tight, and 0.3 will fit together easily. If you're having trouble fitting pieces, you may need to adjust the flow/extrusion multiplier of your printer. This setting may also vary from one filament to the next... oh the joy of 3D printing! :P