CHALLENGE 3: Continuous Rotation With rotation_degrees
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TASK
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Write a script that continuously increases a Sprite2D's rotation in
_physics_process, making it spin steadily in place. Use
rotation_degrees instead of rotation and confirm the sprite still
spins identically.

SOLUTION CODE (attached to the Sprite2D)
--------------------------------------------
extends Sprite2D

const ROTATION_SPEED_DEGREES = 90.0  # 90 degrees per second - one full turn every 4 seconds

func _physics_process(delta: float) -> void:
    rotation_degrees += ROTATION_SPEED_DEGREES * delta

WHY THIS WORKS AS AN ANSWER
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This uses the exact same frame-rate-independent pattern as movement
(SPEED * delta), just applied to rotation_degrees instead of
position - multiplying by delta guarantees the sprite completes a
full 360-degree turn in the same real-world time regardless of the
game's actual framerate.

rotation_degrees and rotation are two different views onto the same
underlying value - Godot stores rotation internally in radians
(rotation), but rotation_degrees is provided as a convenience so
code and designers who think in degrees don't have to convert by
hand. Changing one automatically keeps the other in sync: after one
second at this speed, rotation_degrees would read roughly 90, and
reading rotation directly at that same moment would show
approximately 1.5708 (90 degrees expressed in radians, since
PI radians = 180 degrees). Visually, using rotation_degrees here
produces an identical spinning result to using rotation with a
radian-based speed constant - only the unit used to express the
speed differs, not the actual motion on screen.