Emotional communication reduced to its bare minimum: two stones - when you hold one, the other warms up.
The White Stone is a prototype of a mobile and emotional medium for communication. Two people can communicate by sharing a pair of stones. The stones react to physical contact and mediate this to the other stone, which then becomes warm.
The White Stones are emblematic of what we like to call emotional communication. The point being, of course, that sometimes a little goes a long way. Instead of throwing ever more bandwidth trying to satiate the desire for mediated imtimacy we do the opposite - we try to reduce the communication until all that remains is the message itself, void of any meaning other than that which the recipient gives it.
Tor Nørretranders introduced the concept of exformation in his book The User Illusion (1998). He uses this word to relate to the body of a priori knowledge shared between the sender and receiver of a message. Since they both know what they are talking about, there is no need to actually mention it - it can be excluded. (Exformation is short for explicitly discarded information.)
As an example of exformation Nørretranders mentions the message that was exchanged, via telegrams, between Victor Hugo and his publisher. Hugo, wanting to know about the reception of Les Miserables, simply sent a single character: "?" The publisher understood the message, and responded equally brief to tell Hugo of the success: "!"
What we try to do with the White Stones is also to convey a simple message: I am thinking about you. Right now. All the rest - how much I care, how much I miss you - all that, we leave unspoken. The white stones come in pairs, like the halves of a break-apart heart charm, and the signal is only sent to the other half of the pair.
So far, we only have the design prototypes of the White Stones, we haven't actually built a working prototype.