Scented colouring pens with tactile symbols and braille, so you can tell what the colours are (there is a list of symbols at the end of this blurb).

19 scented pens - Scentos brand:
Dark Red
Red
Orange
Light Orange
Dark Yellow
Pale Green
Light Green
Green
Dark Green
Turquoise (i.e. Greenish Blue)
Light Blue
Blue
Purple
Mauve (i.e Pinkish Purple)
Bright Pink
Brown
Dark Brown
Black
Grey

The basic symbols are as follows:
Red - heart
Orange - circle
Yellow - star
Green - leaf
Blue - moon
Purple - swirl
Pink - flower
Brown - triangle
Black - square
Grey - line

For dark colours, the symbol is followed by a textured block of 4 closely spaced lines.

For light colours, the symbol is followed by one long line. 

If the colour is midway between two colours (e.g. Mauve is Pinkish Purple, Turquoise is Greenish Blue), it will have both symbols on it.
 
These tactile markings are not endorsed by Scentos.
Not suitable for children under 3 years.