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In 3 block towers puzzle, i first kept any one color at bottom and remaining at 2nd and 3rd position that made one tower then i changed the 2nd and 3rd block means 2nd at 3rd postion(top) and 3rd at 2nd position that became 2nd tower.

in this way, now i have put other color block at botttom that was 3rd tower and changed the position of 2nd and 3rd block so got 4th tower.

in this way, now i have put remaining color block at botttom that was 5th tower and changed the position of 2nd and 3rd block so got 6th tower.

in this way, total 6 tower we can make