The Inchworm was a ride-on toy

Toy

A toy is any object that can be used for play. Toys are associated commonly with children and pets. Playing with toys is often thought to be an enjoyable means of training the young for life in human society. Different materials are used to make toys enjoyable and cuddly to both young and old...

 for children produced by the Hasbro

Hasbro

Hasbro is a multinational toy and boardgame company from the United States of America. It is one of the largest toy makers in the world. The corporate headquarters is located in Pawtucket, Rhode Island, United States...

 Corporation, first introduced in the early 1970s. A scooter

Kick scooter

A kick scooter or push scooter, originally scooter, is a human-powered vehicle with a handlebar, deck and wheels that is propelled by a rider pushing off the ground. The most common scooters today have two hard small wheels, are made primarily of aluminium and fold for convenience...

 with yellow

Yellow

Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...

 wheel

Wheel

A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...

s in the shape of a green

Green

Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...

 caterpillar

Caterpillar

Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...

 wearing a yellow hat

Hat

A hat is a head covering. It can be worn for protection against the elements, for ceremonial or religious reasons, for safety, or as a fashion accessory. In the past, hats were an indicator of social status...

, the Inchworm was joint

Joint

A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...

ed under the saddle

Saddle

A saddle is a supportive structure for a rider or other load, fastened to an animal's back by a girth. The most common type is the equestrian saddle designed for a horse, but specialized saddles have been created for camels and other creatures...

 so its wheelbase

Wheelbase

In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels.- Road :In automobiles, the wheelbase is the horizontal distance between the center of the front wheel and the center of the rear wheel...

 could expand and contract. The wheels were constricted by a ratchet mechanism to rotating forward. As the rider bounced up and down on the saddle, the toy moved forward in a way somewhat resembling a Geometer caterpillar

Geometer moth

The geometer moths or Geometridae are a family of the order Lepidoptera...

, with the ratcheting wheels making a clicking sound.

The Inchworm is still available from the Radio Flyer company.http://www.amazon.com/Radio-Flyer-73-The-Inchworm/dp/B000O94Y0Y http://www.radioflyer.com/products/rideon/73.asp and from many other online retailers. http://www.classicredwagons.com/radio_flyer_the_inchworm_73_c14_p27.htm