Thank you! I start off with 3 pieces of wood and draw the pattern out. Then I use a table saw with the blade at 15-20 degree angle and run it through a cut at a time, sliding the wall each time. The cuts are about 1mm wide. Once I have the slots made I use a jig saw… I then make small dowel cuts to glue and attach the wings. I use a nail gun also for extra security and just patch up the holes. I don't have a biscuit router, but when I do, I may try that so that there aren't any holes.
I actually started making simple aircraft carrier coin racks of just the flat tops and used the same concept. Just make the slots first, then cut the flat top out. I'll post a picture of it on here.