Last week I came up with the following diagram and accompanying equation which describes where along the main Ramp of the Altar the minor ramp to the Yesod branched off to the west.
Tiferes Yisrael, in his Temple Diagram §48, indicates that the minor ramps branched off somewhere on the lower half of the main Ramp. When the above equation is solved (I entered it in Grapher, my Mac's built-in graphing program), we get:
This means that the ramp to the Yesod began 13.81 amos from the foot of the main Ramp, or 2.19 amos below its midpoint, which is indeed on the lower half of the main Ramp.
As for the ramp to the Sovev on the east, it is physically impossible to have it branch off on the lower half of the main Ramp and also conform to the Temple standard of 1 amah of height for every 3 amos of length. Since the slope will, in any case, differ from the standard, it appears that we may have the minor ramp to the east branch off at the same point as the ramp to the Yesod on the west. This not only makes the Altar more symmetrical, but having the two ramps directly across from one another shortens the distance that the Kohen needs to walk when descending from the Sovev to bring excess blood to the Yesod.
e = 13.81
This means that the ramp to the Yesod began 13.81 amos from the foot of the main Ramp, or 2.19 amos below its midpoint, which is indeed on the lower half of the main Ramp.
As for the ramp to the Sovev on the east, it is physically impossible to have it branch off on the lower half of the main Ramp and also conform to the Temple standard of 1 amah of height for every 3 amos of length. Since the slope will, in any case, differ from the standard, it appears that we may have the minor ramp to the east branch off at the same point as the ramp to the Yesod on the west. This not only makes the Altar more symmetrical, but having the two ramps directly across from one another shortens the distance that the Kohen needs to walk when descending from the Sovev to bring excess blood to the Yesod.