A test print to help you figure out how much clearance you need for two printed parts to fit into each other.The main peg is a 5mm x 5mm cube. The peg board has holes of the following dimensions:4.8mm x 4.8mm 4.9mm x 4.9mm … 5.8mm x 5.8mmIn my print, the 5.1mm x 5.1mm slot ( 0.05mm clearance per side) gave a good and very tight fit - perhaps for permanent connections. The 5.2mm x 5.2mm square (0.1mm clearance per side) gave a good generally-useful fit.