"The Pedalternorotandomovens centroculatus articulosus came into being (generatio spontanea!) as a result of dissatisfaction concerning nature's lack of any wheelshaped living creatures endowed with the power of propulsion by means of rolling themselves up. So the little animal shown here, known in popular parlance as the 'curl-up' or 'sausage roll', is an attempt to fill a long-felt want.

Biological details are still scarce; is it a mammal, a reptile or an insect? It has a protracted body made up of horny articulated sections, and three pairs of legs the extremities of which resemble the human foot. Placed centrally in the thick, round head (shaped like an acutely curved parrot's beak), are the bulging eyes, on the ends of stalks and sticking far out on either side.

In its fully stretched position this creature can move slowly and gingerly forward, by using its six legs, over almost any type of terrain (it can, if occasion arises, climb up or down steeps, stairways, penetrate undergrowth or clamber over chunks of rock). But as soon as it needs to undertake a long journey and has the advantage of a suitable level path for the purpose, it presses its head on the ground and rolls itself up with lightning speed, pushing itself with its legs, in so far as they touch the ground. In its rolled-up position, it has the shape of a discus, the central axis formed by the eyes on stalks. By pushing out each of its pairs of legs in turn it can get up a high speed. Furthermore, it is thought ot be capable of retracting its legs and freewheeling onwards (for instance when coming down a slope or going full tilt).

Whenever it has reason to do so, it is able to return to its walking position by one of two methods:

    (i) an abrupt stop brought about by suddenly stretching its body, in which case it ends up on its back with its legs in the air;

    (ii) a gradual reduction of speed, using the legs as brakes and coming to a halt by slowly unrolling backwards."

This somewhat-charming whimsical creature (think of a cross between an armadillo, a pill bug and an Amphisbaena) first appears in M.C. Escher's lithograph "CURL-UP" (Wentelteefje) (viewable online at http://www.clowder.net/hop/curlups/CurlUps.jpeg) in 1951 (from which the above text originates, translated from the Dutch) and also appears in the same year's lithograph HOUSE OF STAIRS (Trappenhuis) (viewable online at http://www-scf.usc.edu/~khushboo/escher/Houseofstairs.jpg), where numerous curl-ups are seen scuttling and rolling around in various stages of curl in a CONCAVE AND CONVEX-style perspective-shifting staircases-on-the-walls-connecting-to-the-ceiling typical of Escher's most well-known works.

In German translations the curl-up is known as the Krempeltierchen and en Francais it is given the appellation le roulenboule.