With this loader animation, which is done in pure CSS you can see that it looks like a slider puzzle with multiple squares moving in and out trying to solve the puzzle. This code snippet was designed by Andreas Hjortland.
If you are having trouble with the pen, try the archived copy on GitHub
Multicolour Slide Puzzle Style Loading Animation Snippet
See the Pen loading without gradient by Andreas Hjortland (@andreas_hjortland) on CodePen.0