English: A composite target layout (top) is split into two sub-layouts: vertical dense lines (blue) and horizontal sparse and dense lines (red) due to the incompatibility of the illuminations used for each sub-layout,^[1] when the dense pitch is less than wavelength divided by numerical aperture. The sparse lines require on-axis illumination, while dense lines require off-axis illumination.^[2][3] On the other hand, with off-axis illumination, it is desirable to apply subresolution assist features for the sparse horizontal lines.^[4] So the layout splitting allows this due to extra spaces between lines while the original composite doesn't. Furthermore, the tip-to-tip (T2T) features (circled) also need to be controlled well, but are inherently the wrong orientation, requiring the use of additional cut exposures, as it is not possible to fit assist features.