BubLab

I use this app to calm me dow and it provides a great thinking time and effort

The mission in each level is to clear all the "bubbles". They come in 4 different shapes/colors representing stages of evolution of their kind. The green ones are the top level of evolution. When a green "bubble" is tapped, it dissolves and turns into 4 "bullets", flying off north/east/south/west. When a bullet hits another "bubble", the "bubble" is destroyed. Green ones turn into 4 "bullets", others just get removed. To not make things too easy, there is a limited number of taps per level. The levels get increasingly complex and thus more difficult. Well, there's nothing wrong with this game, except that I find it lame and boring. But maybe, that's just me.

It's a fun great way to pass the time?

The object of this puzzle game is to 'disinfect' your lab by touching the correct blob(s) to set up a chain reaction which will remove all the blobs from the screen. Blobs are 1 of 4 different colours depending on their evolutionary stage (blue, pink, orange, and green); you can only get the chain reaction going by touching a green blob. Touching any other colour of blob makes it evolve. But you're only allowed a limited number of touches per level (I've seen from 1 to 3 so far), so you definitely have to pick the correct blob to start with - otherwise you'll have to replay the level. Difficulty increases as you advance. It's an okay game, very repetitious, not very exciting.