The fact you missed one out on the right hand side is making all OCD.
(
Mu Dinofiddler,
Thu 18 Apr 2013, 10:34,
archived)
It's OK
each image is in two parts. The central line falls between the two middle images. Everything is symmetrical.
(
_Felix 's school of dance and occult sciences,
Thu 18 Apr 2013, 11:31,
archived)