Proposal for the Flag of South Africa, 1927, Four Quadrants Version, the "Senate Flag" 
as requested by User:The_C_of_E at the Illustration Workshop. I used this reference image in creating this.

According to [1], this flag was proposed by the Senate in 1927, inspired by both File:Flag_of_South_Africa_poposal_1927_SAP.svg and File:Flag of South Africa poposal 1927.svg.
Own work
Lommes