For younger children the shapes will need to be pre-cut. Cut the potato in half and then carve basic shapes such a square, a triangle, a leaf etc. If it's easier, you can use a felt tip to draw the shape on and then cut around it. The potato shapes will need to be dried out over night. They will be too wet for printing straight away.

Printing the positive & negative shape

For older children, give each child half a potato. Draw the outline of the shape on to the potato using a felt tip pen. This shouldn't ruin the pens if the potato is dry enough. Pupils can then cut around the shape to make the 'block' for printing. This can be done with small sharp knives or lino cutters. This must be done with caution and supervision is recommended.