Solution grids do not typically include overlays of the shapes, because they would overlap and would be hard to distinguish. For clarity, the shapes have been shown in the solution to the Shapedoku example (see fig. 6).
Because each number appears exactly once in each row and each column, nine of the sides of the indicated shapes is oriented horizontally or vertically. For this reason, shapes can be a little more difficult to visualize when solving Shapedoku puzzles. Students might consider slopes of line segments when identifying parallel and perpendicular sides and consider whether sides are congruent. For example, see the parallelogram using the 2s amd the isosceles right triangle using the 4s in figure 6a.