Need to find this afghan pattern

I made this afghan almost 25 years ago and now my daughter requested I knit her one for her 30th birthday next November. Does anyone know where this pattern comes from or how to do this stitch?

I can’t tell for sure by looking at the picture, is the middle worked in two colors or is that the background showing through?

It’s worked in two colors

Is it the Hoover blanket?

Thanks for the link GrumpyGramma, always wondered how to double knit. Can U tell I’m a newbie LOL!

The one you have isn’t double knit, then. I’m now out of ideas. Sorry I couldn’t help.

I couldn’t find the pattern on my site. Sorry.

It’s some kind of slip stitch pattern.