Hello, this was a quick project to use up some of my smaller off cuts of wood. Probably took about 2-3 hours. Enjoy

Supplies

Wood: various small off cuts depending on what you want.
Super glue
Hacksaw
Drill
Sandpaper
Stanley knife

Step 1: Design

Play around with your off cuts to decide on size and where you want your gaps. I went with a mish mash to give me two heights and two full length rungs for letters. If you have a big block of wood or you only want a small holder then you may only want one or two pieces of wood. Mark out where to cut and cut your blocks.

Step 2: Make Card Slots

I haven't got many photos here because I'm sure there's a better tool or way of doing this, probably on instructables. I marked my card rung then drilled a hole at either end a cut a ridge with a Stanley knife. Then I drilled a series of holes along the line as close as possible and used a combo of Stanley knife, pliers and drill to join the holes together. This was time consuming, not the kneatest and I also broke two drill bits so better ways of doing this welcome in the comments.

Step 3: Finishing Off and Assembling

Everything needed a good sand down at this point. Then a few minutes to super glue things together and it's all done!
Would love to see pics if anyone makes one or has already made a similar project.