diff --git a/TODO b/TODO
index c330c2b..d376fb0 100644
--- a/TODO
+++ b/TODO
@@ -2,3 +2,4 @@ LFO
 Pitch envelope
 Filter envelope
 Polyphony
+Sequencer
diff --git a/data/bg.png b/data/bg.png
index b1a73ef..f4f2bb2 100644
Binary files a/data/bg.png and b/data/bg.png differ
diff --git a/knob.h b/knob.h
index b28daeb..f147a2d 100644
--- a/knob.h
+++ b/knob.h
@@ -4,38 +4,29 @@
 #include<stdint.h>
 #include<string.h>
 
-#define K_AMP         0
-#define K_FREQ        1
-#define K_OSC1_VOL    2
-#define K_OSC1_WAVEF  3
-#define K_OSC1_PHASE   4
-#define K_OSC1_DET   22
-#define K_OSC2_VOL    5
-#define K_OSC2_WAVEF  6
-#define K_OSC2_PHASE   7
-#define K_OSC2_DET   23
-#define K_OSC3_VOL    8
-#define K_OSC3_WAVEF  9
-#define K_OSC3_PHASE   10
-#define K_OSC3_DET   24
-#define K_OSC4_VOL    11
-#define K_OSC4_WAVEF  12
-#define K_OSC4_PHASE   13
-#define K_OSC4_DET   25
-#define K_HP          14
-#define K_LP          15
-#define K_AENV_ATK    16
-#define K_AENV_REL    17
-#define K_FENV_ATK    18
-#define K_FENV_REL    19
-#define K_DET         20
-#define K_LIM         21
+// Knob indexes
+enum
+{
+	K_AMP, K_FREQ, K_DET, K_LIM,
+	K_AENV_ATK, K_AENV_REL,
+	K_OSC1_VOL, K_OSC1_WAVEF, K_OSC1_PHASE, K_OSC1_DET,
+	K_OSC2_VOL, K_OSC2_WAVEF, K_OSC2_PHASE, K_OSC2_DET,
+	K_OSC3_VOL, K_OSC3_WAVEF, K_OSC3_PHASE, K_OSC3_DET,
+	K_OSC4_VOL, K_OSC4_WAVEF, K_OSC4_PHASE, K_OSC4_DET,
+	K_HP, K_LP,
+	K_FENV_ATK, K_FENV_REL,
+	K_LFO1_VOL,
+};
 
-#define K_FMT_PERC    0 // Percent
-#define K_FMT_FLOAT   1
-#define K_FMT_WAV     2
-#define K_FMT_FREQ    3
-#define K_FMT_HEX     4
+// Knob value display formats
+enum
+{
+	K_FMT_PERC,
+	K_FMT_FLOAT,
+	K_FMT_WAV,
+	K_FMT_FREQ,
+	K_FMT_HEX,
+};
 
 typedef struct Knob
 {
diff --git a/main.c b/main.c
index 31a879a..cdef25f 100644
--- a/main.c
+++ b/main.c
@@ -107,48 +107,50 @@ int main(void)
 
 	// Create knobs
 	{
-		uint32_t x=0+12;
-		uint32_t y=164;
+		const uint32_t cell_w=153,cell_h=75;
+		const uint32_t cell_padx=16,cell_pady=18;
+		uint32_t x=0+cell_padx;
+		uint32_t y=cell_h+cell_pady;
 #define knob_space 32
 		create_knob(knobs+K_OSC1_VOL,"",x,y);++total_knobs;
 		create_knob(knobs+K_OSC1_WAVEF,"",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC1_PHASE,"Phs",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC1_DET,"Fine",x+=knob_space,y);++total_knobs;
 
-		x=152+12;
+		x=cell_w+cell_padx;
 		create_knob(knobs+K_OSC2_VOL,"",x,y);++total_knobs;
 		create_knob(knobs+K_OSC2_WAVEF,"",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC2_PHASE,"Phs",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC2_DET,"Fine",x+=knob_space,y);++total_knobs;
 
-		x=152*2+12;
+		x=cell_w*2+cell_padx;
 		create_knob(knobs+K_OSC3_VOL,"",x,y);++total_knobs;
 		create_knob(knobs+K_OSC3_WAVEF,"",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC3_PHASE,"Phs",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC3_DET,"Fine",x+=knob_space,y);++total_knobs;
 
-		x=152*3+12;
+		x=cell_w*3+cell_padx;
 		create_knob(knobs+K_OSC4_VOL,"",x,y);++total_knobs;
 		create_knob(knobs+K_OSC4_WAVEF,"",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC4_PHASE,"Phs",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_OSC4_DET,"Fine",x+=knob_space,y);++total_knobs;
 
-		x=0+12;
-		y=148+90;
+		x=0+cell_padx;
+		y+=75;
 		create_knob(knobs+K_AMP,"Amp",x,y);++total_knobs;
 		create_knob(knobs+K_LIM,"Lim",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_DET,"Fine",x+=knob_space,y);++total_knobs;
 		create_knob(knobs+K_FREQ,"",x+=knob_space,y);++total_knobs;
 
-		x=152*1+12;
+		x=cell_w*1+cell_padx;
 		create_knob(knobs+K_AENV_ATK,"A",x,y);++total_knobs;
 		create_knob(knobs+K_AENV_REL,"R",x+=knob_space,y);++total_knobs;
 
-		x=152*2+12;
+		x=cell_w*2+cell_padx;
 		create_knob(knobs+K_LP,"LP",x,y);++total_knobs;
 		create_knob(knobs+K_HP,"HP",x+=knob_space,y);++total_knobs;
 
-		x=152*3+12;
+		x=cell_w*3+cell_padx;
 		create_knob(knobs+K_FENV_ATK,"A",x,y);++total_knobs;
 		create_knob(knobs+K_FENV_REL,"R",x+=knob_space,y);++total_knobs;
 #undef knob_space
@@ -604,21 +606,24 @@ int main(void)
 		render_image(r,tex_bg,0,0,640,480);
 
 		// Draw waveform
-		SDL_SetRenderDrawColor(r,86,86,86,86);
-		SDL_RenderDrawLine(r,0,70,640,70);
-		SDL_SetRenderDrawColor(r,255,0,0,0);
-		for(size_t i=1;i<SONGSIZE;++i)
 		{
-			float y1=MIN(synth.channel[0][i-1],1.0);
-			float y2=MIN(synth.channel[0][i],1.0);
-			SDL_RenderDrawLine(r,
-					((float)i-1)/SONGSIZE*640,MIN(70-y1*70,140),
-					((float)i)/SONGSIZE*640,MIN(70-y2*70,140)
-					);
+			const uint32_t wf_x=0,wf_y=0,wf_w=153,wf_h=75;
+			SDL_SetRenderDrawColor(r,86,86,86,86);
+			SDL_RenderDrawLine(r,wf_x,wf_y+wf_h/2,wf_w,wf_h/2);
+			SDL_SetRenderDrawColor(r,255,0,0,0);
+			for(size_t i=1;i<SONGSIZE;++i)
+			{
+				float y1=MIN(synth.channel[0][i-1],1.0);
+				float y2=MIN(synth.channel[0][i],1.0);
+				SDL_RenderDrawLine(r,
+						wf_x+((float)i-1)/SONGSIZE*wf_w,wf_y+MIN(wf_h/2-y1*wf_h,wf_h),
+						wf_x+((float)i)/SONGSIZE*wf_w,wf_y+MIN(wf_h/2-y2*wf_h,wf_h)
+						);
+			}
+			/* SDL_SetRenderDrawColor(r,255,255,255,255); */
+			/* SDL_RenderDrawLine(r,0,0,640,0); */
+			/* SDL_RenderDrawLine(r,0,80*2,640,80*2); */
 		}
-		/* SDL_SetRenderDrawColor(r,255,255,255,255); */
-		/* SDL_RenderDrawLine(r,0,0,640,0); */
-		/* SDL_RenderDrawLine(r,0,80*2,640,80*2); */
 
 		// Spectrum analyzer?
 		/* { */
diff --git a/synth.c b/synth.c
index 3c84344..77d5e02 100644
--- a/synth.c
+++ b/synth.c
@@ -136,9 +136,9 @@ void gen_pul(
 		if(freq==0.0)break;
 
 		if(i%cyclelen==points[0])
-			sig=-amplitude;
+			sig=-amplitude*(1.0-phase);
 		else if(i%cyclelen==points[1])
-			sig=amplitude;
+			sig=amplitude*phase;
 
 		buffer[i]=(buffer[i]+sig)/(mix?2.0:1.0);
 	}