flip the direction of y now y increases upwards

turtle-lib/src/builders.rs

@@ -615,7 +615,7 @@ impl TurtlePlan {
     /// Coordinates are in screen space:
     /// - `(0, 0)` is at the center
     /// - Positive x goes right
-    /// - Positive y goes down
+    /// - Positive y goes up
     ///
     /// # Examples
     ///

turtle-lib/src/execution.rs

@@ -247,7 +247,8 @@ pub fn execute_command(command: &TurtleCommand, state: &mut Turtle) {
 
         TurtleCommand::Goto(coord) => {
             let start = state.params.position;
-            state.params.position = *coord;
+            // Flip Y coordinate: turtle graphics uses Y+ = up, but Macroquad uses Y+ = down
+            state.params.position = vec2(coord.x, -coord.y);
 
             if state.params.pen_down {
                 // Draw line segment with round caps

turtle-lib/src/tweening.rs

@@ -400,7 +400,8 @@ impl TweenController {
                 });
             }
             TurtleCommand::Goto(coord) => {
-                target.position = *coord;
+                // Flip Y coordinate: turtle graphics uses Y+ = up, but Macroquad uses Y+ = down
+                target.position = vec2(coord.x, -coord.y);
             }
             TurtleCommand::SetHeading(heading) => {
                 target.heading = normalize_angle(*heading);