Below are step-by-step instructions / videos. If you prefer to watch the entire build process all at once, you may do so here.
Step 1: Measure the ingredients.
Combine equal parts A and B by weight or volume.
Step 2: Mix the silicone by hand or using a mixer.
Step 3: Pour the silicone into the ice cube tray.
Step 4: Hang the tray upside down and rotate every 45 sec for 25 mins.
Instead of a rotational molding machine, two stacks of books can be used to tip the voxels.
Step 5: Place in 60C (140F) oven for 20 mins.
Step 6: Add another layer of silicone.
Step 7: Hang upside down and rotate (same as step 5).
Step 8: Place in 60C (140F) oven for 20 mins (same as step 6).
Step 9: Cut the voxels out from the tray.
Step 10: Form a slice of your design by securing them to a shared bottom layer.
Holes are punched between adjacent voxels that you want to be actuated together as a unit via a shared air inlet.
Step 11: Finalize the slice by trimming away excess silicone and insert tubing.
At this stage you should check for any leaks by filling a beaker with water, submerging the voxels, and inflating them. Bubbles will emanate from leaks, which can then be repaired with Sil-Poxy.