Aquadoodle

Aquadoodle is an activity drawing toy primarily for preschool aged children. The patented invention is based on a hydrochromic ink which causes color change when the user draws with a water filled pen. The user's drawings will remain for several minutes before gradually disappearing.
The hydrochromic ink technology was created by the Pilot Ink Company of Japan [Patent http://www.google.com/patents/about?id=8s0KAAAAEBAJ&dq=6416853], a subsidiary division of the Pilot Pen Company. The product was introduced to Spinmaster Ltd. by toy consultant/inventor David Fuhrer, President of Funanuf, who was instrumental in securing a licensing and distribution agreement for Spin Master to market the toy in North America and other select markets around the world in 2003. Aquadoodle has become the #1 selling preschool activity toy in the world and has won numerous awards including the TOTY (Activity Toy Of The Year), the US toy industry's most prestigious award.