Overview

This is a stackable swatch library in the form of a Tic Tac Toe board. You print the base game (3x3 tile board) and add feet, then peg your swatches in to create a library that grows into a tower as your filament rolls/variants increase. 

Print details

The base set includes the following (with details on time to print for PLA at 0.20 mm Quality in PrusaSlicer): 

• The 155x155 mm swatch game board (in PLA, PETG, ABS, and Plain variants): print time is ~6 hour at %100. This is the chassis for the tower; you print the game board in the base material and then add swatch pieces.
• The 37.5x37.5 mm swatch pieces (in X, O, and double-sided variants): print time is ~26 minutes at 100%. These are the base building blocks of the tower and of the swatch library, and can be printed and added into the model as you acquire new filament. To label with manufacturer and filament type/color, I'm planning to use a sharpie for light-colored swatches, and paint pens for darker colored swatches.
• The foot-pegs for the game board; print four of these for each level that you print and then use them as part of the stacking library assembly.
• The back peg for the swatch piece; these should be super-glued or epoxied into the back for the board if you want to friction fit the pieces into the game board.

Additional notes/ephemera

• To reduce the print time, scale the model and all associated pieces in PrusaSlicer. At 50% the game board print time time is ~1 hour 20 minutes. 
• I tried adding magnets in place of pegs (which you can see in some of the pictures), and re-learned that attention to positive/negative polarity matters ;-).