Viharas were for the purpose of living, Chaityas were assemblies for the purpose of discussions. Further, Chaityas were with Stupas, Viharas did not have stupas.
Ashoka was a patron of Buddhism therefore he used many symbols that are relevant in Buddhism as motifs in the Ashokan pillar. According to Buddhist tradition, Buddha entered his mother’s womb in the form of a white elephant.
EXAMIANS