Rose Oak used to do a veneer he called wavey they had a thin accent down the middle witch was wavey. Some same wood both sides and some different wood. The thing about the straight lines is keeping them centered after profiling.
I have done several sets with accent lines and also did some with a book match splice. Like Mike said… it’s really tough to keep the accent or splice centered in the limb. If your limb mount isn’t perfect and you need to adjust the tracking too much, the lines look weird off center.
It’s easier to do on an ILF limb set up that has lateral limb adjustment. Sorry… I lost those photos in the photo bucket scam…. Kirk