The clever part was reverse engineering the distortion so they could get an undistorted image. Having constructed that in Lego they could then apply the distortion to get the result.

All his Escher constructions are astonishingly accurate, especially given that in real life he's comparatively normal.

In real life he is obviously extraordinary, I don't understand the point of the last comment, "especially given that in real life he's comparatively normal."

The very fact he does this, and shares it makes him extraordinary.

Sounds like British humour to me - if you don't get it that's fine - but don't start feeling aggrieved about it please.