I would do it by making a sort of frame and then use my track saw. You can easily make a track guide for your saw if you don't have one.
The idea is that the portable saw is moving along and supported by the track or guide, and the block is below it at an angle or angles. The saw cuts what it encounters.
A table saw is an option, again the wood is held in a frame or support. For example, take the square block and lift up one end, then clamp it between two pieces of plywood so it is held off the saw table at one end. This will make that tapered cut. Now, put that on a table saw sled at an angle (clamped down) and you will get the compound angle.
I would be tempted to cut it all with my japanese rip saw, just for fun, but you have to like sawing wood by hand with a sharp saw, and it will take a little longer.