Collapse the bottom right string with a purple sphere.
Collapse the bottom left string with a red sphere.
Switch the blue color to white color.
Collapse the left string with a purple sphere.
Collapse the upper left string with a red sphere.
Switch the white color to yellow color.
Switch the yellow color to red color.
Eliminate the bottom right string with a red sphere.
Eliminate the upper string with a purple sphere (the red ones will collapse).