Demos by PIRA

  3B10.10Rubber rope stretched across front of room.
  3B10.10Brass spring on white plastic sheet.
  3B10.30Torsional wave device, large or small.
  3B10.30Torison wave model.
  3B10.50Transverse wave model, hand-cranked.
  3B10.70Transverse 3-dimensional wave model, hand-cranked.