#!/usr/bin/awk -f

BEGIN { FS=OFS="," }
{ for (i = 1; i <= NF; i++) { a[i,NR] = $i }; m = NF; n = NR }
END {
for ( j = 1; j <= m; j++ )
  for ( k = 1; k <= n ; k++)
    printf( "%s%s", a[j,k], ( k == n ) ? "\n" : OFS )
}