Alexander's pike phalanx rolled inexorably forward, locking the enemy's centre and creating openings through which his heavy cavalry could charge. In most of his battles, this combination of steady phalanx and fast, but heavy-hitting cavalry proved the battle winner.
Alexander's phalanx consisted of foot companions (superior pike in DBM) and the rest of the phalanx (ordinary pike). The foot companions were uniformed in liliac, with blue helmets.
A close-packed 6mm pike phalanx looks very impressive. Pictures speak more than 1000 words :)
Alexandrian battle line with the phalanx as the main element. Skirmishers are thrown forward, and the allied spear is in the rear to guard against encirclement (as at the Granicus). The camp is laid out behind the spear, and the left-flank Thessalian cavalry can just be seen. The phalanx visible in this picture is 60 elements big.
A file (4 elements) of foot companions seen from the side. Notice the levelled pikes of the front rows. Also see the uniforms, clearly distinguishable despite the small size of the figures.
A file (4 elements) of Pk(O) seen from directly above. Notice the irregular staggered last rank. Alexandrian pike would fight 8 or 16 files deep; 16 deep is hard to do with 6mm figures so we do 12 ranks and hope no one counts :)
A file (4 elements) of pike, compared to a file of foot companions uniformed in liliac and blue.