Help! Do you know symmetrical opening lines?

I train my 4 year-old son.

My son always wants to have black and he duplicates my (white’s) moves in the opening. ex. 1.d4 d5 2. Nf3 Nf6 3.e3 e6 …..

So, I am thinking to teach an opening which has "symmetrical position" to him.

Do you know such opening line(s) which has symmetrical position, say up to at least 10 moves?

 I call this The infinite loophole

what I see is if either side just wants to stone wall ,after playing e3 each player goes for king indian pg3,bg2, and then Knd2  At this point Black has to think

about how to break down the stone wall

@Scarlet_chessmaster, Altimore, jhbchess

Thank you for the interesting lines.

@pfren

Thank you for the advice. Yeah, I may do it in future.

I believe he realize it soon or later. I will wait until he realize it. He is still young :)