Card Stand ~ 4"x6"

My wife needed a stand to hold these handwriting cards for my youngest as we start our Kindergarten year. I designed this in OnShape quickly and printed it up in some Tianse Green. I designed it for these cards which are about 4"x6", but it'd be good at holding any relatively rigid sheet that's that size or larger or smaller by half as much. Maybe more.

The original OnShape model is here.