vandelay wrote in message ...

I remember taking a look at the new kitchen a potential customer had
had fitted some months earlier. After a freeze up or something (I
forget what) she'd had the devil's own with it and now (then) it was
supported by a bowl that needed regular emptying.

I fiddled with it for hours befor realising that the threads were such
that they only fitted one way. The piece that held the intake and
outlet for the the trap seemed to be fittable in any direction but it
was not.

It was obviously designed to flow one way only. The idiocy in the
design was in making the threads different without altering the
diameters of the connections to make the design obvious.

How she had got it to fit part way before I had a go defeats me to
this day. It worked a treat after the penny dropped. But I was
panicking for a while as I couldn't do with ability and common sense
what they had done with ignorance and desperation.