Solve this ‘wordoku’ in the same way as a sudoku with letters instead of numbers (the nine letters once in each row, column and nine-square cell). Once solved, one of the overall diagonals gives the jumbled surname of a US natural product chemist who was an authority on diterpene alkaloids. He was also an astute art collector, especially of Rembrandt etchings.

This week’s letters are: A E I L M P R S T