Grain direction decides how a board splits. Learn the material before you force your idea onto it.

Every material has a direction it wants to go, and fighting that is how things crack. Wood splits along the grain, fabric stretches on the bias, a voice has notes it can reach easily and notes it cannot. A good idea pushed into the wrong material fails and looks like a failure of the idea. Most of the time it was a failure to look.

Before you start the next build, spend ten minutes handling the stuff you will use. Bend it, listen to it, waste a small piece finding out how it breaks. Those ten minutes separate designing with a material from arguing with it.