"He passed me a sealed jam jar, the contents of which were half rice and half lentils.
'I'm not hungry, thanks,' I told him.
'No, no. I call this device an entroposcope. Shake it for me.'
I shook the jam jar and the rice and lentils settled together in that sort of random clumping way that chance dictates.
'So?' I asked.
'Entirely usual,' replied Mycroft. 'Standard clumping, entropy levels normal. Shake it every now and then. You'll know when a decrease in entropy occurs as the rice and lentils will separate into more ordered patterns - and that's the time to watch out for ludicrously unlikely coincidences.'"