| abstract |
An toy set having at least one section which bears a color memory dye of an electron-supplying organic coloring compound, an electron accepting compound and an ester. The color memory dye assumes a first color below t1 (°C.) and a second color above t2 (°C.), wherein t2>t1, 0≦t1, t2≦50° C. and 5≦t2-t1≦35. Both the first and second colors can be displayed between t1 and t2. For the purpose of determining the proper temperature range for a color characteristic, temperature-sensitive visual indicators are provided. |