What is "takuzu"

Takuzu is a logic-based number placement puzzle. The objective is to fill a (usually 10×10) grid with 1s and 0s, where there is an equal number of 1s and 0s in each row and column and no more than two of either number adjacent to each other. Additionally, there can be no identical rows or columns. Takuzu is distributed in the French publications Le Figaro, Ludojeux. and 20 Minutes

unsolved grid.svg|An unsolved 4×4 Takuzu grid solved grid.svg|The same grid, solved