@DavidKButlerUoA @RogoNic Wrote this earlier but it seems to have got lost.
Pick x,y.
a=x+y
b=a+x=2x+y
c=b+x=3x+y
d=c+x=4x+y
e=c-a=2x
f=d-a=3x
g=e/x=2
h=f/x=3
1=3-2