I don't think numbers should be used....maybe diamond, circle, and square.
Something like this? Dunno if this works:
Doesn't really make sense on the reels:
I disagree with MrGrigri that numbers shouldn't be on this icon; I think that the "777" is iconic enough to represent a slot machine.
Aliases: fruit-machine
, one-armed-bandit
, casino
.
I gave it a shot.
@JapanYoshi All you did is add more complexity, which seems to go against Material guidelines. Additionally, please actually show those on the grid, because I do not believe they fit in a 24x24 box with a 2dp border.
The only reason why I was steering away from the iconic sevens, was because they are too detailed and small at 1x. I also like @JapanYoshi's middle version with the numbers offset...much like our counter
icon.
I'm definitely leaning toward the 7's in the first design. They are a bit more quickly recognizable.
The shapes aren't a bad idea, I'm fine adding a variant if you guys think it would be a good idea. The 7
's are just much quicker to recognize (even at the smaller size).
The offset letters in @JapanYoshi is a bit too detailed imo.
I've tweaked the icon and overlaid the grid.
What are the circles for? The lack of the handle removes visual identify as a slot machine for me.
The hold buttons I'd assume.
That's too much detail, not every slot machine has those. A slot machine, IMO, should consist of the lever and the reels. That's the minimum required to convey what it is.
Most helpful comment
Something like this? Dunno if this works:

Doesn't really make sense on the reels:

slot-machine-2.zip