If the blocks were 9 different colors, then there would be
9 !(factorial) = 362,880 different ways to line them up.
But for each different line-up, there are 5! =120 ways to arrange
the green blocks and you can't tell these apart, 2!= 2 ways to arrange
the white blocks and you can't tell these apart, and 2!=2 ways to arrange
the orange blocks and you can't tell these apart.
So the number of distinct, recognizable ways to arrange all 9 blocks
is
(9!) / (5! · 2! · 2!) = (362,880) / (120 · 2 · 2) = 756 ways.
