The Cartesian Plan

 

Mathematical Mick was planning a trip
to Belfast to visit his kin,
so Mick and his mare mapped a way to get there,
at dawn the next day they’d begin.

They packed up their bags and to bed went the nag,
but Mick spent a night on the sauce --
they set out at dawn; it was after mid-morn
ere he saw they were miles off course.

“Can’t you read X and Y?” asked Mick with a sigh
said the nag: “When plotting, perforce,
though your thinking was good, you shouldn’t have put
Descartes before the horse.”