Here's how to make a play set/play mat that's the perfect size for Lego Indiana Jones figures. In fact, it's more than just a play set/play mat, it's a double play set/play mat so that two can play - and it features different scenes from the Indiana Jones films too: the Swiss Alps from the 3rd film and the Amazonian rain forest of the last in the series. With a few small boxes of Lego and the main characters, this double play mat/play set is a great place to play, as well as being a fascinating craft project for the kids.

• a thick (0.2 inch) plywood board, 15.7 x 20.5 inches
• a small, thin (0.1 inch) plywood board, 15.7 x 7.1 inches
• a spray can of expanding foam (the cheapest environmentally-friendly option)
• acrylic paint in basic colors (blue, yellow, red, black, white) and paintbrushes
• long safety matches, some small pieces of wood, brass wire
• fimo clay
• small sticks of dead wood, dry leaves, pebbles
• small boxes of Indiana Jones Lego with the main characters and a few accessories

First of all, get the kids to draw a plan on paper to show how the play mat/play set will be laid out, which scenes from the films will be represented, what objects they want to see on the mat... The play mat/play set will be cut in two lengthwise by the board in thin plywood, out of which the mountains have been cut out. The thin board is glued to the wood. Props on either side support it while it is drying. The children will draw where the landscape features are to go in pencil on both sides of the board: the road and the border post (which must be flat), for the 'Swiss Alps' set and the outlines of the river banks for the 'Amazonian rain forest' set.

To landscape the play mat/play set, we use expanding insulation foam. It doesn't cost much, but it's not suitable for children to use. So it's the adult who will apply the foam (using the spray can and nozzle) following the plan in pencil indicating where mountainous/flat areas are to be positioned.
The areas in question must be wet a little so that the foam sticks properly to the wood, the foam should be applied outdoors (as it gives off fumes) and the play mat/play set should be left to dry in the fresh air (outside, but in a place sheltered from the rain).

Once the foam has dried, ta da! The landscape is pretty well defined! All that's left to do is start the cutting: form the overhangs and flat areas using a small saw (let an adult do this), the caves and pitfall traps using teaspoons (the kids can do this).

The first part of the painting stage is to create the colors you want to use by mixing the basic colors available. We will apply successive coats of different shades of green, using broad brushstrokes, to the 'Amazonian rain forest' side, as well as to the mountains (the upright central board). The foam must be completely covered with paint (especially in the places it was cut) in order to stop particles of foam becoming detached. On the Swiss Alps side, the clffs and rocks are painted in different shades of brown and the mountains are painted blue-gray, with snow-bound summits. The road will be painted dark gray, to resemble tar.

So, the main parts of the 'set' are in place. Children can now add in more 'natural' elements: dry twigs, leaves and pebbles will be glued on (with all-purpose glue) to represent rocks. Now you just have to make a few accessories - the kind that are straight out of the various Indiana Jones films, that you can make up with LEGO and which will give you as much pleasure as making the play set/play mat itself will have done...