This summer I had a number of doors to do, apparently a chevron design has become popular. The first set was made with the old door standby, Fir, but the later ones were made of Alder and then Soft Maple.
The Fir is not cheap and loves to explode big chunks when under a shaper cutter, but all of that was hidden because the tear outs were in the grooves. However after seeing this I've finally gotten rid of the most hated machine in the shop, my old Craftsman shaper, and replaced it with a Delta machine, I’m told it’s the last model that was made in the USA. It is significantly better though certainly not a heavy duty machine.
I’ve used standard mortise and tenon joinery which allows me to insert the angled infill a few pieces at a time, adjust the spacing for expansion, and then cap the ends off with the rails.