Finally a simple enough attempt... I hope... (at 2am o_O)
It uses 8 key stones, the rest are just surrounding it.
ferdi: Looks fine - only two stones more than necessary :-)
These stones appear in the "best up to now known solution"!
Coconuts: Generally, escape counts as success in a tsumego, so it is probably best to show the entire surrounding white group.
ferdi:To state the above in more detail: 'These are the stones of your solution that show up in the best known solution, so the last bit of work is to complete the position (Reuven has 16 stones, 14 are best, 10 are there, so you have 4 to do so).'
Robert Pauli: Here's mine.