Strawberry Comb Genetics

[Chicken-Eye]

After reading many articles, I still fail to understand the genetics and allele combinations of strawberry combs. At first I thought it was related to the Cushion Comb (Rose + Pea + Smooth) but that didn't make sense. So my new prediction is Rose + Smooth. Is this the correct combination? Also, how did strawberry combs come to be?

Here's my Malay cock Tin Can for a better look. (If you know me, you'll know I love blue backdrops for photos, and sorry for low quality; I saved this photo as JPEG instead of PNG)