MUST-HAVE CHRISTMAS TOYS OF THE 1990s

Let's take a nostalgia trip back 30 years to discover how the most-wanted toys of the festive season season worked

- BEN BIGGS

FURBY

LAUNCHED 1998

Furby was more than just a toy, it was a pet and companion to the children that owned one. This furry electronic friend looked like a small mammal with a beaked mouth and plastic eyes that would open and close using a simple series of gears whenever it talked. Fresh out its box, a factory-reset Furby only spoke 'Furbish' via a Texas Instruments voice synthesiser. This nonsense language was spouted at regular intervals, the code for which was stored on an 80-kilobyte ROM chip. But with time and with more user interactions, Furby would 'learn' to speak its owner's language. In reality, Furby was pre-programmed with a limited number of words and phrases common to the country in which it was sold in addition to Furbish, and it would gradually speak them only after a certain period of time. It was this that gave Furby the illusion of intelligence, enough to convince a child that Furby was indeed smart, if not alive. Sorry to burst your bubble.

STEEL-STEPPING PHYSICS

With just a little nudge, Slinky appears to 'walk' down stairs

1 NUDGE

Friction naturally prevents a Slinky from moving until a sufficient outside force converts the potential energy in its coils into kinetic energy.

2 FALL

Gravity takes it from here as the Slinky falls to the next step, and kinetic energy propagates along the length of the coils as a compression wave.

3 STEP

The back end of the Slinky catches up and overshoots the step due to momentum, restarting the whole cycle. This only stops when friction overcomes it - in other words, the stairs run out.

SLINKY LAUNCHED 1945