LF crypto related height measure for kids

[houseo]

Right now we draw lines on the wall every July 4th to mark the kids height. I've seen friends with skis/surfboards etc. which are cool wall hangers for measuring height.

Is anyone aware of something crypto related for this? I'd be interested. Amazon/Etsy may have something, or for the right thing could be interested in a custom build. Let me know. Thanks!