Hello: any computer science genii(good luck for a good answer)

AND is the same as NOT NAND (since the NAND gate is false if and only if both inputs are true, the NOT then converts this to true if and only if both inputs are true).

So form a NOT gate from a NAND gate and connect it in front of a NAND gate. Then the NAND gate will output FALSE if and only if both inputs are TRUE, other wise it will output TRUE. The NOT in front of it will then then reverse whatever was outputted by the NAND gate so that you get TRUE if and only if both inputs were TRUE, and FALSE otherwise, which is the equivalent to an AND gate.

Thanks; that really makes sense!