This update continue my plan to upscale this cube to 540 cards.

As tricolored cards are meant to be anchors helping players to choose a color combination and stick with it, each of those cards should be powerfull bombs and/or aim the drafter toward a set of mechanical themes. => Finding cards that suit that description is particularly hard for but I feel any of these cards isn't a perfect match for the cube... Eventually, new releases will bring better suitors.

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With these 10 new cards, there are now a proportion of 30/505 three-colored cards wich makes 9.6/162. As a grid draft uses 162 cards and distribute cards between 18 grids of 9 cards, there's more than one three-colored card seen every two grids during a draft. When the cube will reach 540, the proportion of three-colored cards should be 40/540=12/162 wich should make an average of 12 cards of this category seen during a draft.

Because cards of this category cannot be played together most of the time and at least ten of them should be seen during a draft to get a chance of engaging players on any of the 10 three-color combinations, there is a delicate balance to find:

• This category should be seen at least 10 times on average in a 162 card draft: if not, the probability to see all three-color combinations will be pretty low (proportional to less than 1/10!... I know I should do the maths properly but it doesn't seem necessary to get an idea of what proportions I should have).
• This category should be seen less than 20 times on average in a 162 card draft: if it where higher, that mean each grid of nine cards would have a tricolored card in it wich would be a dead card in 8/10 of times (unless a player is drafting four or more colors).
  Hence, 40/540=12/162 is a round number and satisfy these two conditions.

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But there is more to it: When this cube was 180 cards big with only 10 three-colored cards, almost each draft showed every combinations. It was nice as players was sure to get a reward for sticking to a combination early on. But it was also a problem because playing three color was only rewarded by only one specific card. One advantages of having a larger cube is that it allow more variance. A player choosing early on may get between 0 and 4 three-colored cards. If the former isn't appealing and may suggest a switch in that player strategy, having up to 4 three-color bombs in a 40 cards deck may lead to a cohesive and rewarding gameplay.