> I error to the left when aligning on the left side of the
> triangle, and to the right on the right side.

No, you don't... ;]

The left "picture" formed by the numbers 3, 10, 35 and 126
should be a mirror of the right one. It isn't...

But I like the idea of "erroring" to opposite sides. What about
the center column?

gegroet,
Erik V. - http://www.erikveen.dds.nl/