Mailto, when you say
catch the stone’s left and right
do you mean the pebbled blocks, usually at the bottom of the screen? Because those stone blocks do not move; you have to move the colored blocks sideways (left or right) to get around them.
I only learned how to do this by accident, when I noticed that I was moving colored blocks sideways as I matched them up. Of course, it is much more difficult for me to do this when I want to do it!
Hope this helps.