
Ashoka sculpture version a (click image to enlarge).
The "beard" below the central lion's chin consists of independent "ropes", of which the two in the middle form a single lobe or "tongue", sometimes resembling a ring on the coins. Only one hind leg is visible on the bull at the base of the sculpture.
Version b:

Ashoka sculpture version b (click image to enlarge).
The "beard" below the central lion's chin consists of seven independent "ropes". They do not incorporate the lobe pattern of version a. Both hind legs are visible on the bull at the base of the sculpture.
Version c:

Ashoka sculpture version c (click image to enlarge).
The central lion's "beard" forms a relatively compact "panel" below the chin. The central lion has round(-ish) eyes and no visible whiskers.
Version d:

Ashoka sculpture version d (click image to enlarge).
The central lion's "beard" forms a relatively compact "panel" below the chin. The central lion has almond shaped eyes and visible whiskers.
Version e:

Ashoka sculpture version e (click image to enlarge).
The "beard" below the central lion's chin consists of independent "ropes", of which the one in the center is pointed, and the two adjacent "ropes" form a cup around it.
Version f:

Ashoka sculpture version f (click image to enlarge). (If the image is not visible, click here).
In the case of the "f" version, the side lions are "ducking". Accordingly, the distance between the lions' nosetips represents only 63 per cent of the height of the sculpture, as opposed to c. 71 per cent in the other cases.
