So if you scout with obs at 4:15-4:20 and see 1-1-1 with 2 rax being added, you can use this build. As soon as you see a third CC coming down, you can start transitioning. Basically keep making units until you see the third cc. Once you see the third CC you can transition into Colo + gasses + 4th. Take note that if they are going 3-1-1, the earliest they'll get stim is at 6:40, so they won't attack any earlier than that.
| 12 | 0:00 |  | |
| 13 | 0:12 |  | |
| 14 | 0:17 |  | |
| 14 | 0:24 |  | |
| 15 | 0:36 |  | |
| 15 | 0:37 |  | |
| 15 | 0:42 |  | |
| 16 | 0:48 |  | |
| 17 | 0:55 |  | |
| 18 | 1:03 |  | |
| 19 | 1:15 |  | |
| 20 | 1:24 |  | |
| 20 | 1:27 |  | |
| 21 | 1:36 |  | |
| 21 | 1:40 |  | |
| 21 | 1:48 |  | |
| 21 | 1:50 |  | |
| 22 | 1:59 |  | |
| 23 | 2:03 |  | |
| 26 | 2:26 |  | |
| 27 | 2:36 |  | |
| 32 | 2:55 |  | |
| 35 | 3:17 |  | |
| 36 | 3:22 |  | |
| 39 | 3:29 |  | |
| 39 | 3:31 |  | |
| 42 | 3:51 |  | |
| 47 | 4:07 |  | |
| 49 | 4:14 |  | |
| 49 | 4:21 |  | |
| 55 | 4:30 |  | |
| 58 | 4:45 |  | |
| 62 | 5:00 |  | |
| 62 | 5:09 |  | |
| 62 | 5:10 |  | |
| 62 | 5:18 |  | |
| 66 | 5:31 |  | |
| 68 | 5:37 |  | |
| 68 | 5:41 |  | |
| 72 | 5:43 |  | |
| 77 | 6:03 |  | |
| 80 | 6:05 |  | |
| 85 | 6:28 |  | |
| 101 | 6:50 |  | 
