Fair enough. I could only do the 3x3x3 and 5x5x5 after looking up a solution. I was surprised that I found it fairly easy to work out solutions for the Shepherd and Tartan (next post!) cubes as I was no good at working out solutions to the regular cubes.

Here's a vid I made some years ago about solving the 5x5x5, showing the relative simplicity of it: