Thank you, Yasu, for bringing this to my attention.
So I started playing this game called Swift☆Stitch, and it's quite a game. It's very uncomplicated in its design, and it's a colourful puzzle game with a new twist on solving each level. It tests your reflexes like never before, and if you're in need of some serious training, this game is good for that. One of the cool things is that Swift☆Stitch actually comes with achievements as well. But be careful, glancing up to read them might result in you bashing your cursor into a wall.
The controls are simple to use. You can choose to use your mouse (as I did) or your keyboard, and all the while, you're accompanied with pretty nice background music. You can change your control settings, if you like; it's colourblind friendly(!), and you can even select one of the three different game modes. Even though the idea is to go fast, you can turn down or speed up your cursor through each level.
It's a good game; it's a fun game, and it can be hard. Because I left the speed on the default level of four, it was a bit more challenging for me that it might have been if I toned it down. Nevertheless, I really enjoyed myself. If you want to try out Swift☆Stitch, you can go visit the official homepage and download it for your Windows, OSX, or Linux system. You can even take it mobile — I guarantee it'll really help you pass the time.
Hope you like it, and if you do, tell 'er GDR (and Yasu) sent ya!