and the answer is......
Thanks to those of you who decided to guess which of the stencilled leaves my youngest preferred for his tallit stripe.
He hated the fat leaves. He thought they were ugly, pure and simple.
He did love the more willowy looking willow leaves. I love how easy it is to get a fairly naturalistic looking leaf. I really don't draw all that well. But with the stencil, I can fake something that can pass for willow leaves.
Yes the stencil was cut from an index card. Two long and pointy curved shapes. I occasionally flip the stencil. It helps to create the illusion of naturalism.