Soundtrack: Carto — Rearrange the map, and the music rearranges too

Introduction — the first sound to light up on a papercraft island

Searching for the grandmother she lost in a storm, a girl named Carto sets down on an unfamiliar island. In this game that Komugi reviewed, the first thing to reach your ear is a small acoustic melody with soft edges. Against a world that looks like a watercolor pop-up book, Eddie Yu's music fits snugly. What you hear is light plucked strings, a breathy flute-like timbre, and restrained percussion. The tempo is roughly slow, the corners sanded off before you even try to count the beat.

The soundtrack was written by Eddie Yu (credited as soymilkmusic on Bandcamp) and released in October 2020 across 31 tracks. Each piece is short, many closing within one or two minutes. There is no showy orchestra, no propulsive drum kit. Instead there are small, acoustic-leaning timbres chosen to match the texture of the world.

Place a tile, the sound changes - music keyed to place

Carto's puzzle works by picking up fragments of a map, rotating them, and rearranging them so they connect naturally to bring the world into being. You cannot drop a tile with no beach right next to the sea. It is placement logic close to the board game Carcassonne. And this island changes its face by biome: forest, prairie, desert, snowfield - each is assigned its own small piece of music.

Here is the design core of this soundtrack. Ordinary game music advances along time. But Carto's music sounds according to place. When the player assembles tiles and walks into newly formed land, the music switches to that land's timbre. It is telling that the track names themselves read like a map of terrain and feeling - Prairie, Wind, Dust, Lava, Dew, Tunnel. Music summoned by spatial arrangement rather than by a timeline becomes another expression of the central mechanic of rearranging tiles.

And one more hidden line runs through it: the arc of losing a grandmother and finding her again. Bond, Reunion, Mother, Goodbye, Finale. Among a set of rearrangeable little pieces, only these few are placed to carry emotional weight. The terrain music is pale and wide; the story music has names and runs deep. The roles are clearly split.

Short loops that survive long deliberation - friction between thinking time and sound

A tile puzzle is this: place, step back and look, rotate, place again - over and over. The player stares the map down, spending long 'thinking time' right there. If the music carries too much information here, it gets in the way of thought. That Carto's little pieces are uniformly short, low in melodic density, and made of round-cornered timbres looks like a choice to keep the player company through that deliberation in sound.

The loop construction is modest too. Because the head and tail of each piece do not assert themselves strongly, no matter how long the player lingers in a region, the repeat rarely surfaces as 'here it goes again.' It neither escapes into ambient silence nor rushes you with chiptune propulsion. What is here is music that permits you to stay. Through the few minutes when the solution is still invisible, the sound sinks gently into the background; the moment you see it and walk on, the next land's timbre is there to greet you again.

Analogy with the puzzle - the tempo of rearranging

With my habit of measuring everything in BPM, the tempo of solving Carto is a leisurely round trip - place, look, rotate, replace - roughly the speed of walking. No urging beat is needed. Eddie Yu's sound matches that round trip by removing propulsion, easing the tempo, and blurring the outline of the beat. If what works for the trial and error of Baba Is You is a brisk chiptune, what works for the 'rearranging' of Carto is acoustic music as gentle as breathing.

What is interesting is that the solution arrives through spatial reassembly. Rather than advancing in a straight line, you rotate fragments, mesh them, and rebuild the shape of the world. The music, too, is not a linear score but a set of fragments summoned per place. The structure of the act of solving and the structure of the music are built from the same grammar of 'rearranging' - and there I see this soundtrack's greatest virtue.

Tracks worth hearing

First, listen through the whole soundtrack on the official auto-generated playlist. The very flow of short little pieces switching from land to land is the design of this game's music.

Individually, for terrain music try Explore, Prairie, and Wind - samples of pale, wide sound that permits you to stay. For story music, Bond and Reunion, and the curtain-closing Finale. Comparing the 'pale terrain sound' and the 'named emotional sound' from the same composer makes the design of the role split clear. Each track can also be reached individually on Eddie Yu's Bandcamp ↗ and the official OST on Steam ↗.

Closing - what I would steal if I were composing

If I were to carry something home to my own composing, I would steal the idea of 'keying music to place rather than to time.' In games designed so the player lingers long on the same screen, preparing short, low-information, round-cornered fragments per land and summoning them by movement keeps better company with deliberation than writing the score as a single line. And within that pale terrain sound, sink only a few named pieces as emotional anchors - like Bond, Reunion, Finale. It is the allocation of pale and deep that works.

What makes me want to hear it again is a night when I want background music while I work. It does not rush me; it permits me to stay. If you like puzzles about rearranging maps and tiles, comparing it with the generative sound of COCOON or the walking sound of A Monster's Expedition reveals the range of design in 'how to set sound beside thinking time.'

References

・Eddie Yu — Carto (Original Game Soundtrack) Bandcamp

・Steam: Carto (Original Game Soundtrack) official DLC

・YouTube: Carto (Original Game Soundtrack) official auto-generated playlist

・Wikipedia: Carto (video game)