diff --git a/include/heap.h b/include/heap.h
index c93eb8e..8118384 100644
--- a/include/heap.h
+++ b/include/heap.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 
 void heap_init(void *buf);
+uint32_t heap_used(void);
 
 void *malloc(uint32_t size);
 void *calloc(uint32_t count, uint32_t size);
diff --git a/initrd/init b/initrd/init
index 8196511..694c151 100644
--- a/initrd/init
+++ b/initrd/init
@@ -19,5 +19,15 @@ do
 	set y (y + 20)
 while (y < 270)
 
-line 80 250 380 90 511
+#line 80 250 380 90 511
+set purple 511
+do
+	rand 219 > x
+	rand 379 > y
+	rand 219 > i
+	rand 379 > j
 
+	line (x + 50) (y + 50) (i + 50) (j + 50) purple
+	delay 1000
+	set purple (purple + 11)
+while (1)
diff --git a/libinterp.a b/libinterp.a
index f15e956..7884542 100644
Binary files a/libinterp.a and b/libinterp.a differ
diff --git a/run.sh b/run.sh
index 88be7fa..318f1ff 100755
--- a/run.sh
+++ b/run.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
-openocd -f /usr/share/openocd/scripts/board/st_nucleo_l476rg.cfg \
-	-c "init; reset halt; flash write_image erase main.hex; reset run; exit"
+#openocd -f /usr/share/openocd/scripts/board/st_nucleo_l476rg.cfg \
+#	-c "init; reset halt; flash write_image erase main.hex; reset run; exit"
 
-#openocd -f /usr/share/openocd/scripts/board/st_nucleo_l476rg.cfg > /dev/null &
-#gdb-multiarch 
+openocd -f /usr/share/openocd/scripts/board/st_nucleo_l476rg.cfg > /dev/null &
+gdb-multiarch -iex "target remote localhost:3333" out/main.elf
diff --git a/src/clock.c b/src/clock.c
index ab92386..7cb4ecf 100644
--- a/src/clock.c
+++ b/src/clock.c
@@ -54,7 +54,7 @@ void SysTick_Handler(void)
 	// just keep counting
 	ticks++;
 
-	if (!(ticks % 10))
+	if (!(ticks % 4))
 		SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk;
 
 	asm("mov lr, %0; bx lr" :: "r" (lr));
diff --git a/src/heap.c b/src/heap.c
index 5d32a14..0502e76 100644
--- a/src/heap.c
+++ b/src/heap.c
@@ -19,16 +19,27 @@ void heap_init(void *buf)
 	// what to do...
 }
 
+uint32_t heap_used(void)
+{
+	uint32_t total = 0;
+	alloc_t *a = &root;
+	while (a->next > 1) {
+		total += a->size;
+		a = (void *)(a->next & ~(1));
+	}
+	return total;
+}
+
 void *malloc(uint32_t size)
 {
 	task_hold(1);
-	if (size < 16)
-		size = 16;
+	if (size < HEAP_ALIGN)
+		size = HEAP_ALIGN;
 	alloc_t *node = &root;
 	while (node->next & 1 || node->size < size) {
 		if ((node->next & ~(1)) == 0) {
 			node->next |= (uint32_t)(heap_end + HEAP_ALIGN) & ~(HEAP_ALIGN - 1);
-			heap_end += 2 * HEAP_ALIGN + size;
+			heap_end += HEAP_ALIGN + size;
 			node = (void *)(node->next & ~(1));
 			node->next = 0;
 			node->size = size;
@@ -46,7 +57,7 @@ void *malloc(uint32_t size)
 void *calloc(uint32_t count, uint32_t size)
 {
 	uint8_t *buf = malloc(count * size);
-	for (uint8_t i = 0; i < count * size; i++)
+	for (uint32_t i = 0; i < count * size; i++)
 		buf[i] = 0;
 	return buf;
 }
diff --git a/src/main.c b/src/main.c
index 0245801..a946609 100644
--- a/src/main.c
+++ b/src/main.c
@@ -107,7 +107,7 @@ int script_color(interpreter *it)
 		igetarg_integer(it, 2));
 	variable v;
 	v.valtype = INTEGER;
-	v.value = c;
+	INT(&v) = c;
 	v.svalue = 0;
 	isetstr(&v);
 	iret(it, &v);
@@ -120,7 +120,7 @@ int script_rand(interpreter *it)
 	next = (next * 182 + 1829) % igetarg_integer(it, 0);
 	variable v;
 	v.valtype = INTEGER;
-	v.value = next;
+	INT(&v) = next;
 	v.svalue = 0;
 	isetstr(&v);
 	iret(it, &v);
diff --git a/src/task.c b/src/task.c
index 13e4e75..d0cb3f1 100644
--- a/src/task.c
+++ b/src/task.c
@@ -54,7 +54,6 @@ void task_init(void (*init)(void))
 
 	task_disable = 0;
 	init();
-	// you dirty dirty dog
 	/*asm("\
 		cpsie i; \
 		mov pc, %0; \
@@ -65,9 +64,8 @@ void task_start(void (*task)(void), uint16_t stackSize)
 {
 	task_hold(1);
 	task_t *t = task_create(task, stackSize);
-	task_t *next = (task_t *)current->next;
+	t->next = current->next;
 	current->next = t;
-	t->next = next;
 	task_hold(0);
 }
 
@@ -96,12 +94,8 @@ void PendSV_Handler(void)
 		msr psp, r0; \
 		isb; \
 		dsb; \
-	" :: "r" (current->sp));
-
-	// end
-	asm("\
 		cpsie i; \
 		bx lr; \
-	");
+	" :: "r" (current->sp));
 }