diff --git a/graphics/hgr/bubble_universe/Makefile b/graphics/hgr/bubble_universe/Makefile
index b3b3a7e1..8b4f0a38 100644
--- a/graphics/hgr/bubble_universe/Makefile
+++ b/graphics/hgr/bubble_universe/Makefile
@@ -39,7 +39,7 @@ bubble.o:	bubble.s hgr_clear_part.s sin_unrolled.s
 BUBBLE_TINY:	bubble_tiny.o
 	ld65 -o BUBBLE_TINY bubble_tiny.o -C $(LINKER_SCRIPTS)/apple2_c00.inc
 
-bubble_tiny.o:	bubble_tiny.s hgr_clear_part.s sin_unrolled.s hgr_clear_codegen.s
+bubble_tiny.o:	bubble_tiny.s hgr_clear_codegen.s
 	ca65 -o bubble_tiny.o bubble_tiny.s -l bubble_tiny.lst
 
 ###
diff --git a/graphics/hgr/bubble_universe/bubble_tiny.s b/graphics/hgr/bubble_universe/bubble_tiny.s
index 2aea9ddd..4b436876 100644
--- a/graphics/hgr/bubble_universe/bubble_tiny.s
+++ b/graphics/hgr/bubble_universe/bubble_tiny.s
@@ -16,6 +16,7 @@
 ; 2326 bytes -- alignment turned off
 ; 2311 bytes -- optimize mod table generation
 ; 1447 bytes -- first attempt at hgr_clear codegen
+; 1443 bytes -- tail call optimization
 
 ; soft-switches
 
@@ -290,7 +291,6 @@ hposn_low	= $6b00
 
 hgr_make_tables:
 
-
 	;=====================
 	; make /7 %7 tables
 	;=====================
@@ -300,10 +300,9 @@ hgr_make_7_tables:
 	lda	#0
 	tax
 	tay
-
 div7_loop:
 	sta	div7_table,Y
-mod_smc:
+mod7_smc:
 	stx	mod7_table
 
 	inx
@@ -315,25 +314,11 @@ mod_smc:
 	ldx	#0
 
 div7_not7:
-	inc	mod_smc+1	; assume on page boundary
+	inc	mod7_smc+1	; assume on page boundary
 	iny
 	bne	div7_loop
 
 
-;	ldy	#0
-;	lda	#0
-;mod7_loop:
-;	sta	mod7_table,Y
-;	clc
-;	adc	#1
-;	cmp	#7
-;	bne	mod7_not7
-;	lda	#0
-;mod7_not7:
-;	iny
-;	bne	mod7_loop
-
-
 	; Hposn table
 
 ; hposn_low, hposn_high will each be filled with $C0 bytes
diff --git a/graphics/hgr/bubble_universe/hgr_clear_codegen.s b/graphics/hgr/bubble_universe/hgr_clear_codegen.s
index 83c3df52..a5dbcfda 100644
--- a/graphics/hgr/bubble_universe/hgr_clear_codegen.s
+++ b/graphics/hgr/bubble_universe/hgr_clear_codegen.s
@@ -6,7 +6,7 @@ hgr_clear_codegen:
 	;========================
 	; set up output pointers
 
-	lda	#<(hgr_page1_clearscreen)
+	lda	#<(hgr_page1_clearscreen)	; assume both start page boundary
 	sta	OUTL
 	sta	INL
 
@@ -29,7 +29,7 @@ hgr_clear_codegen_loop:
 	lda	#$99		; STA
 	jsr	write_both
 
-	lda	hposn_low,X
+	lda	hposn_low,X	; low is same both
 	jsr	write_both
 
 	lda	hposn_high,X
@@ -77,9 +77,11 @@ hgr_clear_codegen_loop:
 
 
 	lda	#$60			; RTS
-	jsr	write_both
+;	jsr	write_both
 
-	rts				; tail call
+;	rts				; tail call
+
+	; fallthrough
 
 
 	;=============================