diff --git a/README.md b/README.md
index be722ee..302420f 100644
--- a/README.md
+++ b/README.md
@@ -1,22 +1,23 @@
 # waterfall
-A waterfall spectrum analyzer for the ADALM-PLUTO, written in Odin, using fenster and libiio. Only on X11 (for now?).
+A waterfall spectrum analyzer for the ADALM-PLUTO SDR, written in Odin, using fenster and libiio. Only on X11 (for now?).
 This is a project that was made for the University of Twente First year's Electrical Engineering Wireless transmission project of 2023.
 
 ## Dependencies
-X11 (so basically, Linux), [Odin](https://github.com/odin-lang/Odin), [libiio](https://github.com/analogdevicesinc/libiio), bash
+Linux, X11, [Odin](https://github.com/odin-lang/Odin), [libiio](https://github.com/analogdevicesinc/libiio), bash, gcc
 
 ## Building and running
 First you build it:\
 `$ ./make.sh`\
-Then you can run it:\
+Then, connect the ADALM-PLUTO to your pc.\
+Now you can run it:\
 `$ ./waterfall`\
-It should bring up the window. Running it in the terminal is highly recommended.
+It should bring up the window.
 
 ## Usage
-The middle of the screen is the '0-frequency' of the complex fourier transform. Pressing the up-and-down arrow keys changes the frequency that the ADALM 'focuses' on.
-How to actually interpret that is unclear, but I suspect it changes the center frequency as well.
+Pressing the up-and-down arrow keys changes the frequency that the ADALM-PLUTO 'focuses' on, and with it, the center frequency.\
+The center frequency is at the middle of the screen.
 
 ## Details
-It starts at 100MHz, a sampling rate of 60MHz (whatever that entails exactly), and an FFT bin size of 1024.\
+It starts at 100MHz, a sampling rate of 60MHz (whatever that entails exactly), and an FFT bin size of 1024. Every frame is normalized, so if there's no one loud signal, you will see a lot of noise.\
 In this repo, there are functions for reading and writing .WAV files, which can be implemented quite easily.\
 There is currently a memory leak and more wierdness going on with closing the device and destroying the buffer. I am not sure why it won't destroy the buffer properly.
diff --git a/main.odin b/main.odin
index f03993e..d619955 100644
--- a/main.odin
+++ b/main.odin
@@ -9,13 +9,13 @@ import "wav"
 import "iio"
 
 main :: proc() {
-	level :: uint(10)
-	bin_size :: 1 << level
+	level := uint(10)
+	bin_size := uint(1 << level)
 	sample_rate :: 60_000_000
 	focus_freq := 100_000_000
 	history_size :: 800
 
-	info := iio.prep_and_get_device(iio.STANDARD_IP, focus_freq, sample_rate, bin_size)
+	info := iio.prep_and_get_device(iio.STANDARD_IP, focus_freq, sample_rate, int(bin_size))
 	if !info.success do return
 //	defer iio.undo_device(&info)
 
@@ -43,9 +43,11 @@ main :: proc() {
 		delete(freqs_buffer)
 	}
 
-	was_pressed := false
+	arrow_was_pressed := false
+	space_was_pressed := false
+	paused := false
 	for !fenster.loop(fen) {
-		for y := fen.height - 1;  y > 0 ; y -= 1 {
+		if !paused do for y := fen.height - 1;  y > 0 ; y -= 1 {
 			this_line := scr_buf[fen.width*y : fen.width*(y+1)]
 			next_line := scr_buf[fen.width*(y-1) : fen.width*y]
 			copy(this_line, next_line)
@@ -61,22 +63,51 @@ main :: proc() {
 			}
 		}
 
-		pressed := false
+		/* coloured subdivisions */
+		{
+			for k: uint = bin_size >> 2; k < bin_size; k += (bin_size >> 2){
+				x := int(k)
+				y := history_size - 20
+				fen.buf[x + int(fen.width)*y] = fenster.RED
+			}
+			for k: uint = bin_size >> 3; k < bin_size; k += (bin_size >> 2){
+				x := int(k)
+				y := history_size - 10
+				fen.buf[x + int(fen.width)*y] = fenster.RED
+			}
+			for k: uint = bin_size >> 4; k < bin_size; k += (bin_size >> 3){
+				x := int(k)
+				y := history_size - 5
+				fen.buf[x + int(fen.width)*y] = fenster.BLUE
+			}
+			for k: uint = bin_size >> 5; k < bin_size; k += (bin_size >> 4){
+				x := int(k)
+				y := history_size - 5
+				fen.buf[x + int(fen.width)*y] = fenster.GREEN
+			}
+		}
+
+		arrow_pressed := false
+		space_pressed := false
 		freq_jump := 0
 		if fen.keys[ARROW_KEY.UP] {
-			pressed = true
+			arrow_pressed = true
 			freq_jump = 10_000_000
 		}
 		if fen.keys[ARROW_KEY.DOWN] {
-			pressed = true
+			arrow_pressed = true
 			freq_jump = -10_000_000
 		}
+		if fen.keys[SPACE_KEY] {
+			space_pressed = true
+		}
+		if space_pressed && !space_was_pressed do paused = !paused
 
-		if pressed && !was_pressed {
+		if arrow_pressed && !arrow_was_pressed {
 			focus_freq += freq_jump
 			fmt.printf("new center frequency: %d MHz...", focus_freq/1_000_000)
 //			iio.undo_device(&info) /* this crashes, so it's commented out for now, even though it leaks memory */
-			info := iio.prep_and_get_device(iio.STANDARD_IP, focus_freq, sample_rate, bin_size)
+			info := iio.prep_and_get_device(iio.STANDARD_IP, focus_freq, sample_rate, int(bin_size))
 			if !info.success {
 				fmt.printf(" failed :(\n")
 				return
@@ -84,7 +115,8 @@ main :: proc() {
 			fmt.printf(" success!\n")
 		}
 
-		was_pressed = pressed
+		arrow_was_pressed = arrow_pressed
+		space_was_pressed = space_pressed
 
 		if fen.keys[ESC_KEY] || fen.keys['Q'] do break
 	}
diff --git a/make.sh b/make.sh
index 817f923..d8367d2 100755
--- a/make.sh
+++ b/make.sh
@@ -1,3 +1,5 @@
+set -e
+
 (cd iio; bash make_lib.sh)
 (cd fenster; bash make_lib.sh)