diff --git a/tools/grid.py b/tools/grid.py
index 50190da..c9e3125 100644
--- a/tools/grid.py
+++ b/tools/grid.py
@@ -377,10 +377,10 @@ class Grid:
         )
 
     @classmethod
-    def from_str(cls, grid_string: str, true_char: str = '#', default: Any = False) -> 'Grid':
+    def from_str(cls, grid_string: str, true_char: str = '#', true_value: Any = True, default: Any = False) -> 'Grid':
         ret = cls(default=default)
         for y, line in enumerate(grid_string.split("/")):
             for x, c in enumerate(line):
-                ret.set(Coordinate(x, y), c == true_char)
+                ret.set(Coordinate(x, y), true_value if c == true_char else default)
 
         return ret