It's like big-endian v.s. little-endian only worse.
I made the mistake of using y-down for the block coordinates because I was importing from a spreadsheet.
OpenGL of course uses y-up. That means I wrote things I shouldn't have had to. And now I need to fix them before I go any further.
If only it had occured to me to just reverse the rows after I read them in!
I still don't know what the game plan for widget coordinates would be since they are y down.
I might flip the coordinate system for that ... Ugh!!!
I hate coordinate systems!