diff --git a/desk.acc/a2d.inc b/desk.acc/a2d.inc
index 5fec6f3..161f6aa 100644
--- a/desk.acc/a2d.inc
+++ b/desk.acc/a2d.inc
@@ -174,8 +174,12 @@ A2D_UNK_1A      := $1A          ; Unknown - used in calculator before window cre
                                 ; and after destruction
         ;; (input length 1 byte)
 
-A2D_UNK_24      := $24          ; Unknown - used in calculator
-        ;; (no parameters; pass $0000 as address)
+A2D_SET_CURSOR  := $24          ; Change cursor pattern
+        ;; (input not copied)
+        ;; .res 24      2x12 byte bitmap
+        ;; .res 24      2x12 byte mask
+        ;; .byte hotx   hotspot coords
+        ;; .byte hoty
 
 A2D_SHOW_CURSOR := $25
         ;; (no parameters; pass $0000 as address)
diff --git a/desk.acc/calculator.s b/desk.acc/calculator.s
index 73ed083..819646b 100644
--- a/desk.acc/calculator.s
+++ b/desk.acc/calculator.s
@@ -757,14 +757,33 @@ create_window_params_top := create_window_params::top
 
 title:  PASCAL_STRING "Calc"
 
-        ;; param block for $24 call (just before entering input loop)
-L0CE6:  .byte   $00,$00,$02,$00,$06,$00,$0E,$00
-        .byte   $1E,$00,$3E,$00,$7E,$00,$1A,$00
-        .byte   $30,$00,$30,$00,$60,$00,$00,$00
-        .byte   $03,$00,$07,$00,$0F,$00,$1F,$00
-        .byte   $3F,$00,$7F,$00,$7F,$01,$7F,$00
-        .byte   $78,$00,$78,$00,$70,$01,$70,$01
-        .byte   $01,$01
+cursor: .byte   px(%0000000),px(%0000000) ; cursor
+        .byte   px(%0100000),px(%0000000)
+        .byte   px(%0110000),px(%0000000)
+        .byte   px(%0111000),px(%0000000)
+        .byte   px(%0111100),px(%0000000)
+        .byte   px(%0111110),px(%0000000)
+        .byte   px(%0111111),px(%0000000)
+        .byte   px(%0101100),px(%0000000)
+        .byte   px(%0000110),px(%0000000)
+        .byte   px(%0000110),px(%0000000)
+        .byte   px(%0000011),px(%0000000)
+        .byte   px(%0000000),px(%0000000)
+
+        .byte   px(%1100000),px(%0000000) ; mask
+        .byte   px(%1110000),px(%0000000)
+        .byte   px(%1111000),px(%0000000)
+        .byte   px(%1111100),px(%0000000)
+        .byte   px(%1111110),px(%0000000)
+        .byte   px(%1111111),px(%0000000)
+        .byte   px(%1111111),px(%1000000)
+        .byte   px(%1111111),px(%0000000)
+        .byte   px(%0001111),px(%0000000)
+        .byte   px(%0001111),px(%0000000)
+        .byte   px(%0000111),px(%1000000)
+        .byte   px(%0000111),px(%1000000)
+
+        .byte   1, 1            ; hotspot
 
 ;;; ==================================================
 ;;; DA Init
@@ -772,15 +791,15 @@ L0CE6:  .byte   $00,$00,$02,$00,$06,$00,$0E,$00
 init:   sta     ALTZPON
         lda     LCBANK1
         lda     LCBANK1
-        A2D_CALL $1A, L08D4
+        A2D_CALL $1A, L08D4     ; if NOP'd, display renders like a bar code later
         A2D_CALL A2D_CREATE_WINDOW, create_window_params
         A2D_CALL A2D_QUERY_SCREEN, state_params
         A2D_CALL A2D_SET_STATE, state_params     ; set clipping bounds?
         A2D_CALL $2B                          ; reset drawing state?
         lda     #$01
         sta     input_state_params::state
-        A2D_CALL $2D, input_state_params
-        A2D_CALL A2D_GET_INPUT, input_state_params
+        A2D_CALL $2D, input_state_params ; ???
+        A2D_CALL A2D_GET_INPUT, input_state_params ; ???
         lda     ROMIN2
         jsr     reset_buffer2
         lda     #window_id
@@ -839,7 +858,8 @@ loop:   lda     adjust_txtptr_copied-1,x
         lda     #'C'
         jsr     process_key
 
-        A2D_CALL $24, L0CE6
+        ;; previous draws mangle the cursor (why???)
+        A2D_CALL A2D_SET_CURSOR, cursor ; Why not use JUMP_TABLE_CUR_POINTER ?
         ;; fall through
 
 ;;; ==================================================