Mark Sweep's puzzles

Rules Shade some tetrominoes of cells so that no two tetrominoes touch each other orthogonally. Clued cells cannot be shaded, and a clue means that the first tetromino seen in a straight line in the indicated direction is of the shape associated with that letter. Solve online

This puzzle may not really have good aesthetics, but I am quite pleased with the logical flow of it. Rules Shade one tetromino of cells in each region so that all shaded cells form one orthogonally connected area. Two tetrominoes of the same shape may not share a bold border, counting rotations and reflections as the same. No 2x2 region may be entirely shaded. Solve online

Rules Shade some cells so that no two shaded cells are orthogonally adjacent and the remaining unshaded cells form one orthogonally connected area. Clues cannot be shaded, and represent the total number of unshaded cells that can be seen in a straight line vertically or horizontally, including itself. Solve online

The first hybrid on this blog. Shouldn't be too difficult once you understand the interactions between both genres. Rules Divide the grid into regions of orthogonally connected cells, each containing a connected group of white cells and a connected group of grey cells, with the property that the shape of the white cells is identical to the shape of the grey cells, allowing rotations and reflections. In each of these regions, one tetromino of cells is to be shaded so that all shaded cells form one orthogonally connected area. Two tetrominoes of the same shape may not share a region border, counting rotations and reflections as the same. No 2x2 region may be entirely shaded. Solve online The solve link has a second grid to solve the LITS on, if you wish.