A stack polyomino is a self-avoiding convex polyomino containing two adjacent corners of its minimal bounding rectangle. The number of stack polyominoes with perimeter 2n + 4 is the Fibonacci number F_(2n), having generating function sum_(n = 0)^∞ F_(2n) t^(2n) = (1 - t^2)/((1 - t - t^2)(1 + t - t^2)) (Delest and Viennot 1984).

convex polyomino | lattice polygon | self-avoiding polygon