Tonight's show examines the work of David Hart , who has developed a device that helps children who suffer from cerebral palsy to learn to walk.
Alan Yentob , formerControllerof BBC2 and now Controller BBC 1, talks about the BBC2 logo - why it was commissioned and the technical wizardry behind its many variations.
And there's a look at how virtual reality works, and at the complex logistics behind a rose-growing operation in Africa's Rift Valley that supplies the UK retail market. Presented by Desmond Lynam and Jenny Hull.
Producers Martin Lucas and Gill Stribling-Wright Executive producer Alan Boyd
QUESTIONS: please send them to How Do They Do That?, PO Box 4653. London SE 1 9UQ