I made several number buttons for my fiancee's needle roll. The initial plan was to print some buttons with the different sizes for each needle (3mm, 3.25mm, 12mm etc. etc.).To make the buttons small with the number still printable, I worked on several designs. The decimal place as pie-chart, the number as dice pips buttons, dots, bars etc.Here are the different designs but we ended up using a simple number (as it is pretty obvious which needles will be next the button (.25mm right, .75mm left) and inbetween (.5mm).Personally I really like the dice / piechart number combination.Use the design you like and export it from sketchup or copy the part you need out of one of the STL files, or just use them as inspiration to make your own.