Part of my professional background is in icon design (making application and user interface icons) which funnily enough shares some of the same principles as making graphics for custom blocks in Super Mario World. Sadly, with the great flattening of user interfaces I don't get to nearly be as detailed or whimsical as I used to be, alas.

Anyway, I felt like sharing my insight as a designer with you all so that it may be helpful for your game or thinking about drawing block graphics yourself.

Contents

1. What are blocks?
2. Principles for Visual Metaphors
   • Colour
   • Shape
   • Motion
3. Applying the Principles
4. What Not To Do
   • Don't Use Only Colour As A Differentiator
   • Don't Change The Meaning Of Familiar Symbols
   • Don't Be Too "Clever" with Your Symbols
5. Conclusion

What are blocks?

Putting aside the code component of blocks in Super Mario World, we can simply think of them as a purposeful object, often a single tile, that is being added to (or that already exists in) the game. In other words, a block is a doing thing and has a function that is apparent to players when they interact with them.

A block could be as basic as simply being impassable by the player character, or as advanced as inducing some status effect but in every case there is some underlying functionality that needs a visual representation—a metaphor—to convey that function to the player.

Principles for Visual Metaphors

This is a fancy title for this section but don't overthink it, there's really only three core principles that you need to keep in mind when developing a visual metaphor for block graphics: colour, shape and motion (or a lack of it).

Colour

Colour has meaning or can be given meaning. For instance red is usually interpreted by most humans as "danger" opposed to "safety" and we're attuned to notice it (colourblind folks notwithstanding). How colour is used in block graphics can be a big factor in something catching a player's attention and encouraging or discouraging interaction.

Super Mario World is incredibly effective and consistent about its use of colour. Tiles that are points of interest that the player can interact with are yellow, other general purpose tiles are using a blue-pink palette and there is also a neutral (grey) palette for other environmental blocks. Notably, no other foreground elements are using these palettes.

The effect this has is that these tiles stand out from the general environments of Super Mario World and don't share a palette with elements nearby—an exception being pipes which are often colourful.

What this means for choosing a colours for custom blocks is that you want to use a palette that stands out from the rest of your level's environment, or that uses an established palette (like one of the above) to enforce its meaning and how it fits into the base game.

Shape

Some shapes are very widely understood, for example a skull is usually interpreted as "death" or "danger that will result in death" so it can be safely used to represent that. Distinct shapes make things easy to identify at a glance as well as make them less likely to be confused for other elements.

Sometimes a new shape is needed to convey some new or unfamiliar functionality or a new way of interacting in the game. Let's take the cloud tile in Super Mario World. It's a tile Mario can pass through, except for the top, which he can stand on. Nintendo designed the graphics for this tile with a flat top and uneven sides to show that this is a platform, a design which is very unlike other tiles that are solid on all sides.

Let's take a bad example from ROM hacks to illustrate how visual representation is important. The following is a "1F0" (named after the internal tile number in the base game) which is a helper tile for slope tiles that has some unique properties when used on its own—it preserves the momentum of enemies so they will slide or stick to this tile, but Mario passes right through it.

Mario World romhacks use this tile a lot and the convention is to use the graphic below—reusing railing tiles from the Donut Bridge—to represent it.

The trouble is that nothing about these railing tiles can be intuitively interpreted as "this will preserve sprite momentum." The only thing that makes up for the bad visual representation is that it's very widely used so its meaning has enforced by convention, not by its visuals—the 1F0's functionality has been learned by players through association. To frame it another way, one could easily imagine another convention or graphic could have become widespread simply by people making a different choice of tile to represent it.

This is not to say that convention isn't a valid way to establish the meaning of symbols, but sometimes a non-ideal symbol ends up being convention and work will have to be done by newcomers always to learn what it is.

Motion

Animation draws your eye from the surroundings to the thing that has animation, so it can be used to pull a player's attention to your block or can be attended to by players in their peripheral vision since it can be monitored passively.

Coins are an obvious example from the base game since they are an ever-present reward, and them being animated draws the eye (this is a reason they are great for guiding players) but another great example is the muncher.

As a source of danger, it is something to be avoided since it will hurt Mario. In giving the Muncher animation, it makes it easier for players to pick up on in the level environment—even a single muncher on-screen says "look at me" because of it's motion.

Applying the Principles

For a little exercise in applying these principles, let's imagine a new block that the base game doesn't have: a solid tile that breaks permanently when hit with something.

First, we have our functions: it's solid, but also fragile. Secondly, we also want it to be a point of interest for the player that they interact with and not fade into the environment.

With those goals we can lean into the existing principles the base game has developed to help concieve of a graphic:

• yellow tiles are points of interest
• graphics that fill the tile space and have a hard outline are solid

Fragile blocks are not something the game has so we need to think of a new visual metaphor for fragility that we can combine with our existing principles. A common way to represent a fragile item is cracks in the image, so we can go with that.

Now, to combine all our items: a tile that uses the established yellow palette, that has a hard outline, and has cracks running through it to represent a new "fragile" aspect. To do that TV magic thing of cookery shows, here's one I prepared earlier:

This graphic is essentially a variation of the base game's Turn Block graphic—using the same colour, shape and shading—but the new functionality is conveyed by a very exaggerated crack running down the center. The crack is exaggerated to make sure players notice it as a crack over something more subtle.

What Not to Do

With those above principles in mind also you can now avoid some common problem areas for creating custom block graphics.

Don't Use Only Colour As A Differentiator

When a tile shares graphics with another tile but only changes the colour, it runs the risk of doing is confusing players since they have to think in order to remember what colour that colour means.

Here's the classic example: normal (yellow) muncher is "hurt", red muncher is "kill".

The problem with doing this is: at a glance players can't intuitively know what the what the red muncher does differently from the yellow muncher. In other words, how it's different isn't being shown in a way players can be certain.

The thing to do would be to give the "kill muncher" completely different graphics or, if you want to stick with the muncher, redraw the muncher to appear more deadly to make it visually different from a regular muncher.

Don't Change The Meaning Of Familiar Symbols

This also applies to new graphics you may have made for custom blocks already. You should avoid reusing symbols whenever you can so their original meaning or associations are not watered down.

There is a bias towards existing graphics for blocks that makes what they originally represent hard to overcome in new contexts. For example, making the coin graphic represent water would be foolish.

But say you decided that a red exclamation block would represent a hurt block, or other source of danger—red does usually mean danger after all—which is not a wholly unreasonable idea.

The problem would be that the change is too subtle (just the palette), and not a big enough alteration to overcome people thinking it is a regular Switch Palace block so they may jump on it thinking it is a solid platform.

Don't Be Too "Clever" with Your Symbols

When creating a new symbol to represent a block's purpose, the simpler the better. Trying to be cute or clever or rely on extended metaphors is a recipe for poorly communicating your block's functionality.

Let's say we take our breakable block from the above section and instead of the graphic we came up with based on our principles we gave it a cheeky graphic like: a cracked egg.

While this is cute, it falls apart as an effective representation for our block and has some issues:

1. It doesn't look like a solid block, it looks like an egg, and could be confused for scenery or a sprite.
2. An eggshell, while fragile, isn't the best metaphor to convey "fragility" for what will be a solid block.
3. It doesn't share visual traits with other interactable blocks so it doesn't benefit from familiarity with those.

This is not to say you can't use silly graphics for your functional blocks sometimes but it helps to try and find ones that are good at representing what your block does as best as you are able.

Conclusion

A lot of what I wrote are broad principles, but they are some things that should be relatively easy to keep in mind when trying to think up new graphics for blocks.

As long as you consider how your block fits into the environment of your levels when it comes to its colour being distinct or not, it's shape being unique while not being overly clever or too subtle, and whether or not it has animation to draw attention, you'll be okay.