Suttas that detail the four attainments

[alaber]

Just found a one year old post that answers my question. There are reference to MN 121 and MN 106.

Can we attain Arupavacara Jhana without first going through Rupavacara Jhana?

My understanding is that Buddha learned Arupavacara Jhana from his teachers and Buddha discovered Rupavacar Jhana. I also understand that Arupavacara Jhana is a projection from fourth Jhana. Am I correct?