Thinker

 is the forty-ninth level of Bloons Junior. To complete it, pop any of the Bomb Bloons, then shoot down to pop the single bloon on the bottom. Shoot the dart right to pop the two Bonus Dart Bloons and the Lightsaber Bloon that will pop an Ice Bloon. Then pop the Spiky Bloon on the left and the Tack Bloons above in any order.