I cut the squares out, easiest to make a cardboard template
Stripes can go every which way, and will end up looking good.
Use charm squares too if you like. Arrange them on the backing and sew from the back side.
Trim well, cut corners and turn to correct placement.
I poke the corners out with a chopstick.( I live in the Islands so have plenty.)
They will be a little rounded.
I dyed my ticking in coffee.
These are a great use for all kinds of fabric bits. They can all be different.