So, let's round this off with part 3 of physical design - UI and spatial/gestural elements. How a mechanic is physically presented to the players and represented in-game can completely change its impact. There's a ton of science that go into this stuff, so this is just a taste.

UI design can change how complicated a game looks in some very fundamental ways, as well as profoundly affecting ease of play. The specifics of mechanics also have psychological impacts on the players, and must be crafted with care.

My first experience with this was back during a playtest of the Game of Thrones boardgame. The very early versions used dice, and a roll of a 1 meant one of your units died to enemy archers (1-2 if they had heavy archers). Predictably, I basically wiped myself out during a siege.

That moment was so unpleasant as a player that it has stuck with me as a learning moment ever since. I've tried hard since never to let a player roll a die that will actively harm themselves on a bad result. It's okay to fail, but to be actively punished also is crushing.

So, the "X" (miss) sides on the dice in Descent 1st edition were within my accepted tolerance, and in fact, as the Overlord I'd often sit there "hexing" the heroes' dice calling for a miss in a critical moment...and sometimes I'd get it, too, much to their superstitious horror.

But elements such as the "you blow yourself up on a 1 on d6" for the Orks in 40K...I can't handle that as a player and don't include it as a designer. It's too tilting for me, and I think the unfun for the one player is too severe for the other player's mirth to make up for it.

That's just how a mechanic can land emotionally. How a mechanic is depicted can improve or hinder player learning. @eric_lang and I both often do a thing where we don't tell players how to physically do something in early playtests and instead watch to see what they naturally do.

Certain gestures / motions feel more natural in certain contexts, and you can often sniff this out by quietly observing players acting in a vacuum. I often try to be a bit vague about fussy physical details in rules as well, to accommodate multiple player types.

Play Cosmic Encounter with 3 different groups, and you'll probably see the planets set up at least 3 different ways. Some players line them up, nice and tidy. Others make an organic-looking 'solar system', while others form little patterns all their own. It doesn't hurt anything.

Some things are good practice though, like card layouts. Most players, left- and right-handed, fan their cards so the upper left corners are visible, as that's how standard poker cards are laid out (at least in the West, generally), so the upper left is valuable real estate.

If you have card costs or basic values of some sort, and the players will be holding the cards in-hand, put them there in the upper left. That makes them easy to read. Down the left and across the top are the next most valuable spots.

Anything put in the lower right should be info that's not needed when the cards are held in hand, because it will be almost completely invisible.

Similarly, if I have multiple copies of the same card, I try to make sure they have the same art. It's not just being cheap - the art is a visual short-cut for the players. Once they've played the game awhile, they'll know what a card does with just a glance at its art.

But really, UI design is taught in colleges, people make their whole careers doing it, and I know I've barely scratched the tip of the iceberg here. Don't worry, though. I'll revisit the topics I've discussed here tonight in the future.