Perhaps one of the ice cubes floats lower in the water and therefore more heat is transferred to the water which makes it melt faster.
(more heat; is transferred; to the water) (the water; makes; it melt faster) Context(the water makes,List([97, 118))):(it; melt faster; )
the water makes,List([97, 118))
more heat the water it
is transferred makes melt faster
to the water
it melt faster