tree=:conew&'kdtree' (2,3), (5,4), (9,6), (4,7), (8,1),: (7,2)
   timespacex 'nearest__tree 9 2'
0.000487181 19328
   build0 (2,3), (5,4), (9,6), (4,7), (8,1),: (7,2)
   timespacex 'nearest0 9 2'
3.62419e_5 6016