Think Fast! - 15x15

What’s this? A themeless! Well, kind of. I prefer making themed puzzles, but this was my first honest attempt at a themeless puzzle that I made well over a year ago. After finding it in my archives of saved files, I felt that it was still fun and deserved a home somewhere. You’ll discover that the central three-stack all share a theme hinted at by the title, with the central intersecting entry being a fun bonus. Is it a quasi-themed puzzle? A themeless with a mini-theme? Hurry up and tell me! The clock is ticking!