Polymath 529

[BigMac]

Anyone else struggling with the grid? For example, 12a and 13a seem to elide, as do 26a and 29a... ... but then make 5d and 21d very dificult to complete.

[Lie-in King]

There is an error in the grid. It clears up if you -

Tippex the black squares at line 5, column 8 & line 13, column 10
Blackout the squares at line 5, column 10 (line 5, column 11 becomes 13 across - 7 letters)
& line 13, column 8 (line 13, column 9 becomes 29 across - 9 letters)

[BigMac]

Thanks, Lie-in King.

Worked it out - just confused for a while.