In reply to Steve Parker:
So these three gentlemen are applying for a job on a building site.
The foreman asks George "What is the difference between a joist and a girder"
"Easy", says George "A joist is a beam made out of wood, a girder is a beam made from Steel"
So the foreman sets George to work, and asks Andrew in "What is the difference" says the foreman "between a girder and a joist"
"A girder is made from steel" says Andrew "and is used to make Irn Bru. A joist is made from wood"
So the foreman sets Andrew to work, and gets Patrick in
"Patrick, what is the difference between a girder and a joist"
"Well, to be sure" says Patrick, reinforcing racial stereotypes "Goethe wrote Faust and Joyce wrote Ulysses"
Y.