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Although it's luck-based, I do like this rule so I thought I'd illustrate it here.

Depending on your preference Arisu will be applied when a player wins after reaching or wins with a concealed hand. The first unused Dora indicator is flipped on the dead wall and if it matches a tile in the winning hand then a chip/tip (or bonus double) is awarded, the next tile is flipped and the process continues until you get a tile with no matches. You're looking for exact matches so it's not like the Dora system where for example a 3p indicator makes 4p the Dora. If you get two matches you get two chips/doubles, etc.
In this first example the player opposite me won the hand (killing my flush attempt). She flipped the first tile, got 8s and one match, flipped again, got 4m and two matches, flipped, got 7s and one match, flipped, got 1m and no matches so then stopped. She won four chips. (It's rare to get that many matches but it makes a good example.)
This was a fun example from earlier today - the player to my left won with Kokushi which happened to maximise his potential for getting matches. He flipped 1p with one match, north with one match, red dragon with one match, 1m with one match, west with one match and finally 3p with no matches. In this case it was necessary to continue into the live wall.

(I was playing here with two Dora which is why there are sixteen tiles in the dead wall instead of the usual fourteen. Also green fives!)

I've seen this optional rule in three video-games:

In the game based on the Mukoubuchi manga (DS) Arisu is applied on concealed winning hands and you win bonus Han.

In Mahjong Taikai (DS) it's only on Riichi wins and you get tips.

In Mahjong Haoh: Dankyuu Battle 3 (PS3) you can specify Riichi/concealed/all wins and you earn chips which will be worth 2/5/10 thousand each in the final reckoning. One chip per matching tile for a Ron win or three chips for Tsumo. (This game was the source of the photos above.)

Hmmm, seems interesting! I wonder what happens if you run out of live wall tiles? (if it's almost the end of the round or haitei etc)

...and/or there are several active Kan Dora indicators? I guess you just stop and it's your bad luck.

It'll rarely be an issue though - usually you get either no matches or just one so it's uncommon to flip more than two tiles, maybe three.