Rules & objective
Shade cells so each row sums its shaded column positions to the right-hand clue, and each column sums its shaded row positions to the bottom clue. Positions start at 1. Empty cells contribute zero.
Controls
Arrows select · Numbers enter · Backspace erases · U undoes
Worked example
With column weights 1, 2, 3, 4, selecting columns one and three totals four for that row. The clue is not merely a cell count.