At some point in time, the Powerfix Wall mount pegboard changed the holes from squares to circles, and the square peg won't fit into the circular holes unless you trim the corners with side cutters.
Since this isn't very elegant, I made this remix.
Use 8mm rods for inner holes and two 10mm rods for outer holes.
REMIXED FROM: https://www.thingiverse.com/thing:3069136
The author marked this model as their own original creation. Imported from Thingiverse.