I often had this in a scaled-down windowed mode on my 2nd monitor to fill up the 'in-between times' while I was playing other games e.g. waiting for matchmaking queues or waiting for afk friend(s) in group.

It's a neat little concept. The progression is paced well as it allows you to develop a set of rules in your mind (stages A-Z contain ~24 puzzles each with a common characteristic in each stage). These rules really help as you progress into the stages which start to combine them.

I often had this in a scaled-down windowed mode on my 2nd monitor to fill up the 'in-between times' while I was playing other games e.g. waiting for matchmaking queues or waiting for afk friend(s) in group. It's a neat little concept. The progression is paced well as it allows you to develop a set of rules in your mind (stages A-Z contain ~24 puzzles each with a common characteristic in each stage). These rules really help as you progress into the stages which start to combine them.