Sunday, having installed a new fence post, new metal meshing and part of the concrete wall.

WSJ: Track Set for Daytona Race After Crash

Dr Post's system uses magnets made of an alloy of neodymium (a rarish metal), iron and boron.

ECONOMIST: Maglev trains

He told me of a box on his route that has a steel I-beam for a post and, riding astride it, a regular mailbox set inside a much bigger metal box, the space between the two filled entirely with concrete.

FORBES: Zero Dollar Fix