The tertiary colour here is blue. (Red is primary, and green secondary.)...The tertiary colourMost people know that you can pick a primary and secondary colour in Paint - primary is left-click, secondary is right-click. But did you know there is a tertiary colour controlled by CTRL+click?
In case you didn't guess, this means that you can use the tertiary colour to paint by holding CTRL while click-dragging the cursor in whatever tool...cliquez sur le titre pour lire la source s.v.p.