User blog comment:Derpinator9001/Bullet Hell Fangame/@comment-24170389-20150605182119/@comment-24170389-20150618172109

I've done that a lot of times, it's basically easy. Though, as I don't work with GM scripts, I'll only give a D&D version:

Create event: Set a variable called aim to 0.

Alarm event: Put 8 blocks of "Create moving instance", with the direction of each being "aim" + a multiple of 45. The multiple of 45 shouldn't be larger than 360 (but can be equal).

Still on the alarm event, put other 8 blocks of "Create moving instance", and do the same you did with the first 8 blocks, except it's - instead of +, and also put a - before aim. Then put Alarm 0 in 5 frames (or 10 frames, idk) on the end of everything.

Step event: Set variable aim relative to 1.

Now test it and see how beautiful this rip-off from a pattern in Touhou 8 is.