swipe gesture question

C4Workspace.m

//
//  C4WorkSpace.m
//  Examples
//
//  Created by Greg Debicki.
//

#import "C4WorkSpace.h"

@implementation C4WorkSpace {
    C4Shape *s;
}

-(void)setup {
    s = [C4Shape ellipse:CGRectMake(0, 0, 100, 100)];
    s.center = self.canvas.center;
    [s addGesture:SWIPELEFT name:@"swipeLeft" action:@"leftSwipe"];
    [self.canvas addShape:s];

}

-(void)leftSwipe {
    s.fillColor = C4RED;
}


@end