drracket coding of bouncing ball, below code the ball does not move, pls help to advise

#lang racket

$($require $2$htdp$/$image$)$

$($require $2$htdp$/$universe$)$

$($define WIDTH $605)$

$($define HEIGHT $535)$

$($define BALL$-$RADIUS $10)$

$($define TOP $(+0$ BALL$-$RADIUS$))$

$($define BOT $(-$ HEIGHT $1$ BALL$-$RADIUS$))$

$($define LEF $(+0$ BALL$-$RADIUS$))$

$($define RIG $(-$ WIDTH $1$ BALL$-$RADIUS$))$

$($define$-$struct ball $($x y dx dy$))$

TOP

BOT

LEF

RIG

$($define BALL $($circle BALL$-$RADIUS "solid" "white"$))$

$($define MTS $($rectangle WIDTH HEIGHT "solid" "green"$))$

$($define B$1($make$-$ball $(/$ WIDTH $2)(/$ HEIGHT $2)4-3))$

;check if ball near edges

$($define $($touch$-$top? b$)$

$(<=(+($ball$-$y b$)($ball$-$dy b$))$ TOP$))$

$($define $($touch$-$bot? b$)$

$(>=(+($ball$-$y b$)($ball$-$dy b$))$ BOT$))$

$($define $($touch$-$rig? b$)$

$(<=(+($ball$-$x b$)($ball$-$dx b$))$ RIG$))$

$($define $($touch$-$lef? b$)$

$(>=(+($ball$-$x b$)($ball$-$dx b$))$ BOT$))$

; Bounce the ball off the edges

$($define $($bounce$-$top b$)($make$-$ball $($ball$-$x b$)(+$ TOP $1)($ball$-$dx b$)(-($ball$-$dy b$))))$

$($define $($bounce$-$bot b$)($make$-$ball $($ball$-$x b$)(-$ BOT $1)($ball$-$dx b$)(-($ball$-$dy b$))))$

$($define $($bounce$-$lef b$)($make$-$ball $(+$ LEF $1)($ball$-$y b$)(-($ball$-$dx b$))($ball$-$dy b$)))$

$($define $($bounce$-$rig b$)($make$-$ball $(-$ RIG $1)($ball$-$y b$)(-($ball$-$dx b$))($ball$-$dy b$)))$

; Move the ball

$($define $($glide b$)($make$-$ball $(+($ball$-$x b$)($ball$-$dx b$))(+($ball$-$y b$)($ball$-$dy b$))($ball$-$dx b$)($ball$-$dy b$)))$

; Handle mouse click to create a new ball

$($define $($handle$-$mouse b x y event$)$

$($cond $[($equal$?$ event "button$-$down"$)($make$-$ball x y $(-5($random $11))(-5($random $11)))]$

$[$else B$1]))$

$($define $($render$-$ball b$)$

$($place$-$image $($circle BALL$-$RADIUS 'solid 'white$)($ball$-$x b$)($ball$-$y b$)($empty$-$scene WIDTH HEIGHT 'green$)))$

; Determine the next state of the ball based on its position

$($define $($next$-$ball b$)$

$($cond

$[($or $($touch$-$top? b$)($touch$-$bot? b$))($make$-$ball $($ball$-$x b$)($ball$-$y b$)($ball$-$dx b$)(-($ball$-$dy b$)))]$

$[($or $($touch$-$lef? b$)($touch$-$rig? b$))($make$-$ball $($ball$-$x b$)($ball$-$y b$)(-($ball$-$dx b$))($ball$-$dy b$))]$

$[$else $($make$-$ball $(+($ball$-$x b$)($ball$-$dx b$))(+($ball$-$y b$)($ball$-$dy b$))($ball$-$dx b$)($ball$-$dy b$))]))$

;Main program start here

$($big$-$bang $($make$-$ball $(/$ WIDTH $2)(/$ HEIGHT $2)44)$

$($on$-$tick next$-$ball$)$

$($on$-$draw render$-$ball$)$

$($on$-$mouse handle$-$mouse$))$