> That case was not a "look and feel" case.

It was a look and feel case. The "look" was the appearance of the blocks and of the game board, and the "feel" was the way the blocks moved.

> Mino literally just copied all of the artwork from Tetris. As the artwork was a fundamental part of the game, the judge found that in this very exceptional situation, copyright was violated.

"artwork" is too imprecise in this case. Xio Interactive made their own assets while looking at Tetris, and the judge found that the appearances of the blocks were too similar and that the board dimensions were identical. Regarding the manner of copying [1]:

> While there might not have actually been "literal copying" inasmuch as Xio did not copy the source code and exact images from Tetris, Xio does not dispute that it copied almost all of visual look of Tetris.

[1] https://scholar.google.com/scholar_case?case=180648822600252...

Regarding the blocks themselves [1]:

> Similar bright colors are used in each program, the pieces are composed of individually delineated bricks, each brick is given an interior border to suggest texture, and shading and gradation of color are used in substantially similar ways to suggest light is being cast onto the pieces.

Indeed, Mino should've had different colors. I agree that Mino didn't need shading to suggest 3D lighting (same what), but the mentions of interior border and texture were terrible reasoning because the Tetris blocks appear flat or slightly convex while the Mino blocks appear prominently concave [2] (different how; i.e. different expression of the similar existence of lighting) in a way that nudges my trypophobia. Meanwhile, the merger doctrine [3] should have applied to the "individually delineated" aspect of the blocks.

[2] https://en.wikipedia.org/wiki/File:Mino-tetris-comparison.jp...

[3] https://en.wikipedia.org/wiki/Idea%E2%80%93expression_distin...

Xio Interactive lost the case, as they should've. The colors between identical pieces, the perceptual lightness of those colors, and the colors of the background and GUI are things Xio could've changed without affecting the gameplay. I don't know whether Xio copied the positions of the different GUI elements, but Xio should have switched GUI objects from the top to the bottom or in between, or from the left to the right.

Everything below this line is bonus. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I take issue with most of the other things the judge points out while examining "look and feel". Regarding the board dimensions [1]:

> it is not a rule to have the playfield be exactly 20 units by 10 units

Yes it is. I did mention the difficulty of having a shorter board in my previous comment, though what I should've focused on was the combination of board height and gravity. Gravity is a rule, and higher gravity can be easier or harder for the player to deal with depending on the board dimensions. Additionally, changing the horizontal width alters the math [B1] of the stacking even apart from the gravity and affects the mental and time efficiency of moving the pieces to the desired horizontal positions [B2]). The size of a tennis court is a rule. You can play on different court sizes, but tennis tournaments choose specific court dimensions to the centimeter [B3]. The size of a chessboard is a rule. The size of a bowling lane is a rule. If it affects gameplay, it's a rule. (Even deliberately poor contrast can be a rule as in horror games with low lighting in dark environments, though there is no shortage of color combinations and GUI layouts with high contrast.)

[B1] https://harddrop.com/wiki/Parity

[B2] https://harddrop.com/wiki/Movement_Finesse

[B3] https://olympics.com/en/news/tennis-court-markings-dimension...

Another excerpt [1]:

> Similarly, Mino also displays "garbage" lines, "ghost" pieces, and a preview of the next piece to fall in order to enhance game play as does Tetris.

Garbage lines are a rule and sometimes a game mode. Of course, Xio Interactive did not need to include no more than and all of the exact game modes that the Tetris game had (which may or may not have happened). Choosing which game modes to include or exclude can be copyrighted expression, but I don't think copyright should protect the game modes themselves, since the design of each game mode affects the gameplay. The ghost piece makes the game much easier for low-skill players, and the next piece preview affects players of all skill levels. The judge calls it "enhanc[ing] gameplay", but the information that a player is and is not allowed to use in a game is a rule! The more pieces you see ahead, the more proactively you can ensure a clean stack. As I'm writing this, I'm realizing that applying a general "feel" test to games can lead a judge to dubious exceptions to the idea–expression distinction. An illustrative excerpt [1]:

> Again, there are almost unlimited options for expressing the pieces' movement and rotation

For movement, that's utterly wrong. For rotation, less so. The merger doctrine applies to the directions of piece movement, and movement speed is a rule. The faster the game lets the player move a piece left/right, the easier the game. (Additionally, the piece's visual position should match the actual position. Having the piece lag behind or pull ahead of where it really is would mess with players' reaction times.) Rotation affects gameplay as well. Instant rotation has been a thing since at least as early as Tetris on the NES. Making non-instant rotation purely a visual effect built on instant rotation in the code might not affect high-skill players, but will affect low-skill players. Meanwhile, the code implementation of rotation affects gameplay for everyone. Without wall kicks [B4], rotation states fall under the merger doctrine. With wall kicks, the things that a player can and cannot do change dramatically. Most of the "feel" of a Tetris-like game comes from the functionality accessible to the player. You can or cannot move the pieces up. You can or cannot rotate a piece near or inside a given formation. You can or cannot move the piece faster by holding a direction button than repeatedly tapping the direction button. You have 0 seconds, N seconds, or M movements left to continue moving the piece after the piece touches ground.

[B4] https://harddrop.com/wiki/Wall_kick