Quantum-dot Cellular Automata (QCA) is a candidate technology to replace CMOS. It is a novel nanotechnology which promises extra low power, extremely dense and very high speed structure for designing any arbitrary function at nano scale. In QCA circuits, a suitable arrangement of QCA cells is of great importance. In previous designs, there has been a shift between 90 and 45 QCA cells. In this paper, novel arrangements for QCA cells are introduced. Using these arrangements, a simple even parity generator with different word sizes (i.e., 4, 8, 16 and 32) is presented. It is implemented using a bottom up design approach from a dense and robust QCA XOR gate. In this paper, QCA circuits are implemented and simulated using QCA designer. Simulation results demonstrate that new designs surpass the common designs in terms of area and complexity.