Nick, I believe Dennis Loomis originally PM'ed me about your system, which is GREAT! I use it with the Mnemonica deck. Thank you!

Lcwright1964 opined:
I guess it depends on what one considers "aesthetic". Blue Sharpies on a blue card will leave an off-colour "smear" that is highly visible under some light angles. So I would deem that "functional".

Indeed. Which is why I will duck the trouble, despite my aesthetic preference for blue, and go for red decks with the red Sharpie.

I Don't use a marked deck very often. But when I did I used the Numbers from Mem deck and just scratched the two flowers on a bike with a razor blade. 1-8 going up 9 going in from the top one and 0 don't scratch. It's easy and you can't really see unless you riffle and look.

In my last deck I tried out using a binary marking system and I found that it seemed to pass the riffle test. I'm assuming that this is due to the fact that since any given mark has a 50% chance of being there, a mark is rapidly blinking on an off so fast that it isn't perceived as movement the same way it would be if it only had a 10% chance of being marked.

Interesting!

One question though: Who administered the riffle test? Was it you, or some spectator that was trying to determine if you were using marked cards?

I assume it was a spectator, but I just want to make sure.

It was me administering the riffle test. I was trying to show someone how I marked them so I was going to use the riffle test to help them see the marks, and I found that they were still really hard to see.

Another thing that I noticed with using binary marks is that if you have a completely mixed deck and you want to get into stack order, you deal the cards face down into 4 different piles based on the smallest two binary marks you are left with 4 piles containing cards in a mod 4 type arrangement. So pile one would have 1,5,9,13... pile two would have 2,6,10,14... pile three would have 3,7,11,15... pile four would have 4,8,12,16.... Because of this setup you can perform "a subtle game" by giving each of 4 spectators a single pack, only instead of just calling out the name of a card and expecting the spectator holding that card to hand it to you, you can actually rotate through the 4 spectators one at a time because you know they will be holding the next card. Hope this makes sense.

Harry Anderson published a binary card marking system in his Eight Brass Monkeys notes in 1982

It may have also appeared in Magick.