change a shape within a flat (non-layered) logo to a gradient color range
Hi, I'm trying to figure out how to change the top half of the wave graphic (see arrow) to the rainbow gradient used for the BF icon.
The lasso tool doesn't work for me--it won't select. And using the pen selector tools doesn't work because as I'm plotting around the outside edge, AI fills the selection as I go, so half way through, I can't see the last part to select because it's covered by the fill.
Previously someone suggested creating a mask but that was for the whole object, not selecting a small shape within a photo.
Thank you for your help.

