honeybee33’s reference
 
because short rows are the miracle-drug of knitting
Circular Intarsia - Technique 3
 
Lucia Liljegren detailed a short-row technique on her website in the creation of circular argyle socks, but it could be used for just about any intarsia ITR.
Basically, you work a certain portion of each block of intarsia by itself, turning back-and-forth, and use short-rows and wraps to create the shape.  For instance, to create the top of an argyle diamond (the triangle), you would stop and wrap at 2 sts in on every row.  Then, on the colorblock next to that one, you’d work the same, but when you got to the end of the row you’d also knit (or purl, to maintain stockinette) the next stitch of the first colorblock, working in any exposed wraps.
A very similar technique was described by Suzann Thompson in an article in Threads magazine June 1992 issue; also published in Knitting Around the World, 1993, Taunton Press.  She worked each argyle diamond separately, but instead of wraps, she employed a series of slipped-and-turned stitches labeled an “S” or “Z” (depending on which side of the diamond they were on) increase or decrease (depending on whether you were on the top or the bottom of the diamond).  The “S” or “Z” increase or decrease left a telltale thread that was subsequently picked up when knitting the next diamond.
Both of these techniques work quite handily for evenly sloped shapes like the diamonds in argyles, but I believe they would also work with more amoebus blocks of color.  I have yet to personally try them.
If you just haven’t had enough, check out “Circular Intarsia - Technique 4.”