Generate a simple flat vector hand icon for a rehabilitation game UI in exactly the same visual style as the reference icon. Show the back of the hand (dorsal view), with the palm facing downward around a therapy ball. The hand should be fully wrapped around a spherical ball in a natural power grip. The fingers should curl underneath the ball, while only the upper parts of the fingers and knuckles are visible from above. The thumb should wrap around the side of the ball naturally. The ball should be partially visible on both the left and right sides of the hand, clearly showing that it is enclosed inside the grip. The hand should visually cover the top of the ball, with only the edges of the sphere visible around it. Keep the anatomy simplified into clean grouped shapes. Use a solid white fill with a clean medium-blue outline matching the reference icon. Rounded corners, consistent outline thickness, minimal detail, flat vector style, no realism, no textures, no gradients, no shadows, transparent background. Center the hand and ball, keeping the icon suitable for clean SVG export. Preserve the exact same proportions, stroke weight, corner radius, and overall design language as the reference icon.

The image shows a black and white line drawing of a person's hand holding a ball against a white background.