Penny Arcade

Ping Pong as card game: the design of Penny Arcade’s Paint the Line

Ping Pong as card game: the design of Penny Arcade’s Paint the Line

“Good game designers are always thinking about, and making games, even in their spare time.”—Clint Hocking, GDC 08. That quote was the initial spark that lit the fire for the Paint the Line: Expandable Card Game. There were a lot of other factors involved, but that message was the one that set me to work on, and most importantly, challenging myself to make a game outside of my day job, which also happens to be making games. It may seem ridiculous for someone who makes games for a living making more games in their spare time, but consider the professional artist who stops to sketch an interesting person sitting in the airport or museum, or the professional photographer who always has some kind of camera with them and looks at the world through a photographer’s lens. Even professional animators have the Animation Mentor program; a master class in returning to their roots in animation. But for game designers, at least at the time, there really wasn’t anything out there which encouraged a daily exploration of themes, mechanics, or aesthetics. So I took Clint’s advice and just did it. As it turns out it’s fairly easy to challenge yourself to make a game in your spare time. The difficult part is actually making good on the promise. I considered for a moment using a pre-existing video game engine, but that required resources and learning curves I didn’t have the time, money, or energy to chase down. Besides, game design doesn’t need an engine. It only needs mechanics, and those can be found on playgrounds, in board games, stadiums, hell, you could make a game out of pocket lint if you’re creative enough. I figured, hey, why not make a collectible card game? Those have a ton of assets that need to be balanced, therefore a good game design challenge and, while we’re at it, let’s pick something difficult that’s probably never been made into a card game before: Ping Pong. Crazy, right? A collectible card game based on Ping Pong? I didn’t care about sales potential or demographics; I just wanted a really good challenge, and this seemed about as hard as anything I could come up with.


The game had to represent the escalation of high level play in Ping Pong. If you’ve ever seen an Olympic or Professional Table Tennis match on YouTube, you can see players start serving close to the table, and by the end of the point they seem to be swinging-for-the-fences and standing ten feet off the end of the table. The game also had to feel like Ping Pong. Lots of card games out there are good games, but I don’t feel any analog to what I’m supposedly doing, so I wanted to make sure the aesthetic of playing a game of Ping Pong was somehow represented in the card game. I also wanted a trumping system. I wasn’t sure how it would get there, but I knew that I had to incorporate Rock-Paper-Scissor style action into the game’s core. This was in part to keep things simple, but also because it lends to a “high power” feel of play, and that’s always desirable when making a competitive game. I thought I had nailed the RPS thing on the first try, in that I knew I needed to make different kinds of shots. Initially I had like five different kinds of shots, since I was using a shotgun technique of just throwing everything on the table and seeing what stuck out as fun. Those were whittled down to three shot types, which is a mechanic we call The Advantage System. This is how it works:

  • A Lob Shot has Advantage over a Spin Shot
  • A Spin Shot has Advantage over a Drive Shot
  • A Drive Shot has Advantage over a Lob Shot

The idea behind the Advantage System is that if Player A uses a Lob Shot, and Player B returns a Lob with a Drive Shot, he has “Advantage,” and gets the higher of the two numbers represented on the card to make his shot with. Having the advantage means you are either making your shot even easier, or your opponent’s next shot that much harder. This system is fairly elegant now, but it was rough when I first started out. I had imagined that cards would have an Offensive and Defensive value, and that you could choose how you wanted to play that card, and there would be times it was advantageous to do one or the other, but that system was a near complete disaster. It wasn’t fun, it was confusing, and I was pretty confident there was nowhere to push it. I was attempting to incorporate the Trumping system into the card values; that an Offensive value of “8” would just beat a Shot that only had a “5” or something, and what wound up happening is every point would wind up the same way: the high card always won. That’s not fun, and it created a binary decision on the part of the player: “Do I have a card higher than my opponent’s card?” This mechanic didn’t lend itself to any sort of strategy. So I threw it out, although I kept the “Offensive and Defensive” idea and converted it to “Normal and Advantage” values for the shots, and tried to use those number values on the cards in a different way. I decided to see what would happen if you threw a d20 to try and make that target number.

The Feel of a d20

Incorporating the d20 took a lot of internal and external debate. When I get negative feedback about the d20, and this is usually when someone is rolling low, I try and smile and nod and not be impatient, because what the person giving me the feedback doesn’t realize is that I’ve already gone over the information they’re about to give out a hundred times in my my head already. “Dice rolls are too random,” they say. “At least using two d10s would give players a 'median' of numbers to aim for and be more predictable than a single d20,” they say. “Nobody wants randomness in a card game,” they say. Trust me, I’ve heard it all. I’ve even said it all. But based on playtesting, it’s all wrong. People love that d20. Sure, they love to hate it. Nobody likes rolling a 1, but everyone loves rolling 20’s. Rolling the d20 to hit your target number, or making your “shot,” has accomplished two things. First, it covered a large part of that Aesthetic of Ping Pong I was looking for. The shot cards themselves are super fun and clever and evoke an epic “Ping Pong” feel, but people smile when we show them they’re going to use a d20 as a symbolic ping pong ball during play. There is just a unique charm about using a d20 in a card game. Sometimes we have to remind people in playtests to take their full turn (draw a card, play Stamina, play or use a Shot Card, etc.) because they’ll just pick up the d20 and start getting ready to roll it. Also, the d20 added drama. It removed a large part of that binary decision making process of “I have the higher card and therefore I will win” and replaced it with a fuzzy gray area of play. It demands strategy. It forces you to think about math, probability, and statistics: “What were the last 4 rolls? Were they all insanely high? Statistics dictate I now have a higher probability, not chance, of rolling low. I might want to use a better card now rather than waiting to use it later.” It creates emotion: People get nervous about rolling that die as the target number creeps up. They stand up from their chairs on game point, like poker players going all-in. There is downright electricity in the air when the game comes down to 10-10 and every roll could possibly end the match. The one thing that the game was still missing, however, was that feeling of escalation in Ping Pong.

The Escalation Deck

I’m honestly a little bit fuzzy on how the Escalation Deck came about. I know that I had decided to try rolling on a set increasing target number, and use the shot cards to “buy down” that shot number, or use the shot cards to make your opponent’s roll worse (sending a negative to your opponent’s next roll), but I think initially we were just writing the escalating target number down on a piece of paper and using a pencil as a pointer and sliding the pencil every time someone made a roll. That didn’t last long, since we would forget to slide the pencil every turn (it was sitting next to the score sheet waaayyy over there). We needed a more reliable way to remind the player what that target number was, and how to communicate to them that they need to advance it. Eventually someone had the idea to print a bunch of cards up with the Target Number printed up all huge-like on it, and put it inbetween the two decks/players so that you couldn’t miss it. I even decided that since this had become Cold War Ping Pong, that we should color code the deck to go from green to red as the Target Number escalated all the way up to the dreaded 20: the highest possible base Target Number you could have in the game*. “The Doomsday Clock” was born. It was impossible to miss; here was this giant constant reminder of how hard your shot was going to be right there, staring you in the face, every turn. But like everything in Paint the Line, even the Escalation Deck had its humble not-so-great beginnings. Originally it advanced by one, and I think started at a 7 or an 8. This created two problems:

  • Games were taking too long (and we didn’t know why at the time).
  • Having players serve with a target number of a 7 or an 8 was just a touch too harsh.

So we made some tweaks. I remember Kiko and I lamenting via email that games were just taking way too long. Even seasoned playtesters were taking an hour to get through a single game, and most games were “decking out,” which means players were running out of cards in the deck. I remember just staring at the entire system of cards, trying to figure out how to make the game play faster. Like, where is there a clock in a card game? Where is there a series of sequential numbers whose order or scale could be tuned to be faste—OH the Escalation Deck is a clock! It seems super obvious now, but was almost an epiphany at the time. We decided to try two different courses of action, but the first thing we tried: remove the odd cards and lower the service number to a 6 had already solved our problems. The games were now taking 30 or so minutes for the seasoned vets, and the use of the 6 as the lowest base target number (for service) meant that even if you didn’t use a shot card, your serve had a 75 percent chance of being successful, which was pretty good. It struck a sort of perfect balance in both time and scope (of shot probability), and it even yielded an unexpected bonus: Every shot in the game was suddenly important. The Escalation Index going up by one every turn just didn’t feel dangerous. It felt trivial. Conversely, having it go up two digits each turn felt scary. Each shot now mattered now more than ever. You couldn’t shrug off having an 8 target number, because your hit on the 8 was going to give your opponent a base 10 target number on his next turn, and then your very next return was going to be based on a twelve. And holy shit suddenly this 8 matters, because your next shot was going to be much harder. We had a game that was becoming increasingly fun to play.