diff --git a/assets.md b/assets.md
index 6ea7497..2b4ad5f 100644
--- a/assets.md
+++ b/assets.md
@@ -22,7 +22,9 @@ PPM 8bits channels | In-game `RRRGGGBB` value | Name
 `0x00_00_00` | `000_000_00` | Black
 `0x00_00_FF` | `000_000_11` | Blue
 `0x00_FF_00` | `000_111_00` | Green
-`0x77_77_77` | `011_011_10` | Gray
+`0x99_50_00` | `010_001_00` | Brown
+`0x77_77_77` | `011_011_10` | Dark gray
+`0xB3_B3_B3` | `100_100_10` | Light gray
 `0xFF_00_00` | `111_000_00` | Red
 `0xFF_00_FF` | `111_000_11` | Pink
 `0xFF_80_00` | `111_100_00` | Orange
diff --git a/build.ts b/build.ts
index 2a64ba7..1b97447 100755
--- a/build.ts
+++ b/build.ts
@@ -41,7 +41,9 @@ const spritesMatchingStrings = {
   0x00_00_00: '0b000_000_00',
   0x00_00_FF: '0b000_000_11',
   0x00_FF_00: '0b000_111_00',
+  0x99_50_00: `0b010_001_00`,
   0x77_77_77: '0b011_011_10',
+  0xB3_B3_B3: '0b100_100_10',
   0xFF_00_00: '0b111_000_00',
   0xFF_00_FF: '0b111_000_11',
   0xFF_80_00: '0b111_100_00',