diff --git a/clicket.rkt b/clicket.rkt
index 03dd596..f4bfab6 100644
--- a/clicket.rkt
+++ b/clicket.rkt
@@ -54,7 +54,7 @@
                            [label "Owned: 0"]
                            [auto-resize #t])])
     (new button% [parent button-panel]
-         [label (~a "Buy " (clicker-name cl) " (" (clicker-price cl) "¢)")]
+         [label (~a "Buy " (clicker-name cl) " (" (clicker-price cl) "¢, " (clicker-cps cl) "CPS)")]
          [callback (λ (b e)
                      (when (>= clicks (clicker-price cl))
                        (set-clicker-count! cl (add1 (clicker-count cl)))
@@ -66,16 +66,20 @@
 (new-inc-button left-side "Clicket?" clicks)
 
 ; clicks on a timer
-(struct clicker (name price multiplier (count #:mutable)))
+(struct clicker (name price cps (count #:mutable)))
 (define all-clickers (list
-                      (clicker "mouse"      10    1   0)
-                      (clicker "coder"      150   5   0)
-                      (clicker "paren farm" 1000  10  0)))
+                      (clicker "mouse"        10    1    0)
+                      (clicker "coder"        250   15   0)
+                      (clicker "paren farm"   1000  40   0)
+                      (clicker "define mine"  2500  75   0)
+                      (clicker "git portal"   9999  200  0)))
 (for ([cl all-clickers]) (new-buy-button builtins cl))
 ; prevent tab panel from resizing to a panel with arrows
 (send right-side min-width (send right-side get-width))
 
 ; define your own clickers
+(define init-multiplier 50)  ;desired CPS * init-multiplier  = cost to define clicker
+(define price-multiplier 25) ;desired CPS * price-multiplier = cost to buy clicker
 (define definer-panel (new group-box-panel%
                            [parent left-side]
                            [label "Define custom clicker"]))
@@ -84,9 +88,19 @@
                         [label "Name"]
                         [style '(single  vertical-label)]))
 (define clicks-field (new text-field%
-                        [parent definer-panel]
-                        [label "Clicks per second"]
-                        [style '(single  vertical-label)]))
+                          [parent definer-panel]
+                          [label "Clicks per second"]
+                          [style '(single  vertical-label)]
+                          [callback (λ (f e)
+                                      (define (v) (send f get-value))
+                                      (define (v-num) (string->number (v)))
+                                      (unless (v-num)
+                                        (send f set-value (regexp-replace* #rx"[^0-9]+" (v) "")))
+                                      (send init-price set-label "Init price: 0")
+                                      (send cl-price set-label "Clicker price: 0")
+                                      (when (v-num)
+                                        (send init-price set-label (~a "Init price: " (* (v-num) init-multiplier)))
+                                        (send cl-price set-label (~a "Clicker price: " (* (v-num) price-multiplier)))))]))
 (define price-panel (new group-box-panel%
                          [parent definer-panel]
                          [label "Prices"]))
@@ -95,12 +109,29 @@
                         [label "Init price: 0"]
                         [auto-resize #t]))
 (define cl-price (new message%
-                        [parent price-panel]
-                        [label "Clicker price: 0"]
-                        [auto-resize #t]))
+                      [parent price-panel]
+                      [label "Clicker price: 0"]
+                      [auto-resize #t]))
 (new button% [parent definer-panel]
-     [label "Define"])
-; TODO implement callback
+     [label "Define"]
+     [callback (λ (b e)
+                 (define name (send name-field get-value))
+                 (define cps-str (send clicks-field get-value))
+                 (define cps (string->number cps-str))
+                 (define price (* cps price-multiplier))
+                 (define cost (* cps init-multiplier))
+                 (when (and name cps-str (>= clicks cost))
+                   (set! clicks (- clicks cost))
+                   (define cl (clicker name price cps 1))
+                   (set! all-clickers (append all-clickers (list cl)))
+                   (new-buy-button definitions cl)
+                   (unless selected-tab
+                     (switch-tab right-side #f)
+                     (send right-side set-selection 1))
+                   (send name-field set-value "")
+                   (send clicks-field set-value "")
+                   (send init-price set-label "Init price: 0")
+                   (send cl-price set-label "Clicker price: 0")))])
 
  
 ; setup timer
@@ -111,8 +142,8 @@
                       (set! cps 0)
                       (for ([cl all-clickers])
                         (when (= 0 (modulo timer-ctr 10))
-                          (set! clicks (+ clicks (* (clicker-multiplier cl) (clicker-count cl)))))
-                        (set! cps (+ cps (* (clicker-multiplier cl) (clicker-count cl)))))
+                          (set! clicks (+ clicks (* (clicker-cps cl) (clicker-count cl)))))
+                        (set! cps (+ cps (* (clicker-cps cl) (clicker-count cl)))))
                       (send click-msg set-label (click-str))
                       (send cps-msg set-label (cps-str))
                       (set! timer-ctr (add1 timer-ctr)))]))