Instructions
Square
Place one large triangle on a hard surface so the long side is vertical and the right angle points to the right like a right arrow. Align the other large triangle so the long side is horizontal and the right angle is facing down like a down arrow. Slide the triangles together so their short sides align while they maintain their specified orientation.
Rotate one small triangle until its long side is horizontal and the right angle is pointing up like an up arrow. Slide this triangle beneath the right-pointing large triangle so the bottom point of the large triangle and the left point of the small triangle meet.
Fit the square into the space left by the small triangle and the right-pointing large triangle. You must align the square at an angle, like a diamond, to fit in this space. Fit the second small triangle so its right angle is pointing left and its right angle meets the right angles of both large triangles.
Slide the parallelogram into place to the right of the second small triangle and below the top large triangle. Fit the medium triangle into the remaining space beneath the parallelogram, small triangles and square to complete the large square.
Rectangle
Align the long sides of both large triangles so the triangles match up to form a square. Slide one small triangle next to the square made by the large triangles so the long side is diagonal and the short sides are vertical and horizontal. The right angle of the triangle should be touching the bottom right corner of the square the two large triangles form.
Match one of the long sides of the parallelogram with the long side of the small triangle. The two short sides of the parallelogram should be horizontal. Slide the square into place above the parallelogram so it fits into the right angle made by the parallelogram and the square formed by the large triangles.
Position the medium triangle so its long side is vertical and its right angle is pointing to the left. Slide it into place so the lower diagonal edge lines up with the diagonal long side of the parallelogram. To complete the rectangle, slide the final small triangle into place in the 45-degree angle left between the square and the medium triangle.
Rhomboid
Rotate one large triangle so its long side is diagonal and its short sides are at the bottom and right of the shape. Align one small triangle so its long side is diagonal and its short sides are on the bottom and left of the shape. Slide the small triangle over next to the large triangle so the two right angles meet and the vertical sides match up. The small triangle will only reach half way up the side of the large triangle.
Place the parallelogram next to the small triangle so one long side matches up with the long side of the small triangle. The short sides of the parallelogram should be horizontal. Slide the square into the right angle above the parallelogram and to the right of the large triangle. All edges should align without any overlap.
Position the remaining small triangle so its long side is diagonal and its short sides are at the top and left of the shape. Slide it in place so the vertical short side of the triangle aligns with the right side of the square.
Rotate the medium triangle so its long side is vertical and its right angle points to the left. Slide it into the right angle created by the long side of the parallelogram and the long side of the second small triangle.
Position the final large triangle so its long side is diagonal and its short sides are to the left and top of the shape. Slide it into place so its vertical side lines up with the vertical long side of the medium triangle to form a parallelogram.