diff --git a/atomics.c b/atomics.c
new file mode 100644
index 0000000..4ff5e5d
--- /dev/null
+++ b/atomics.c
@@ -0,0 +1,43 @@
+#include <stdatomic.h>
+#include <stdio.h>
+#include <threads.h>
+
+atomic_int x; // _Atomic int
+
+int thread1(void *arg) {
+    (void)arg;
+
+    printf("Thread 1: Sleeping for 1.5 seconds\n");
+    thrd_sleep(&(struct timespec){.tv_sec = 1, .tv_nsec = 500000000}, NULL);
+
+    printf("Thread 1: Setting x to 3490\n");
+    x = 3490;
+
+    printf("Thread 1: Exiting\n");
+    return 0;
+}
+
+int thread2(void *arg) {
+    (void)arg;
+
+    printf("Thread 2: Waiting for 3490\n");
+    while (x != 3490); // spin here
+
+    printf("Thread 2: Got 3490--exiting!\n");
+    return 0;
+}
+
+int main(void) {
+    x = 0;
+
+    thrd_t t1, t2;
+
+    thrd_create(&t1, thread1, NULL);
+    thrd_create(&t2, thread2, NULL);
+
+    thrd_join(t1, NULL);
+    thrd_join(t2, NULL);
+
+    printf("Main    : Threads are done, so x better be 3490\n");
+    printf("Main    : And indeed, x == %d\n", x);
+}
diff --git a/cjson/.gitignore b/cjson/.gitignore
new file mode 100644
index 0000000..904fe7c
--- /dev/null
+++ b/cjson/.gitignore
@@ -0,0 +1 @@
+cjson*
diff --git a/cjson/Makefile b/cjson/Makefile
index ff5f5ab..1b69237 100644
--- a/cjson/Makefile
+++ b/cjson/Makefile
@@ -1,12 +1,22 @@
-CC ?= gcc
-CFLAGS ?= -Wall -O2 -lcjson
+CC ?= cc
+CFLAGS ?= -Wall -O2 -I.
+LDFLAGS ?=
 
 TARGET = main.elf
-SRC = main.c
+SRC = main.c ./cjson/cJSON.c
 
 $(TARGET): $(SRC)
 	@echo CC $@
 	@$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
 
+CJSON_URL = https://github.com/DaveGamble/cJSON/archive/refs/heads/master.tar.gz
+CJSON_TAR = cjson.tar.gz
+CJSON_DIR = cJSON-master
+
+cjson:
+	curl -L $(CJSON_URL) -o $(CJSON_TAR)
+	tar -xzf $(CJSON_TAR)
+	mv ./cJSON-master ./cjson
+
 clean:
 	rm -f $(TARGET)
diff --git a/cjson/main.c b/cjson/main.c
index 30c5d87..e54004b 100644
--- a/cjson/main.c
+++ b/cjson/main.c
@@ -1,5 +1,6 @@
-#include <cjson/cJSON.h>
+#include "cjson/cJSON.h"
 #include <stdio.h>
+#include <stdlib.h>
 
 char *build_set_level_command(int level) {
     cJSON *root = cJSON_CreateObject();
@@ -9,10 +10,12 @@ char *build_set_level_command(int level) {
     // char *message = cJSON_PrintUnformatted(root);
     char *msg2 = cJSON_Print(root);
     cJSON_Delete(root);
-    return msg2; // Remember to free this when done!
+    return msg2;
 }
 
 int main(void) {
-    printf("%s\n", build_set_level_command(10));
+    char *msg = build_set_level_command(10);
+    printf("%s\n", msg);
+    free(msg);
     return 0;
 }
diff --git a/config_ini/conf.h b/config_ini/conf.h
index d158605..415a7e0 100644
--- a/config_ini/conf.h
+++ b/config_ini/conf.h
@@ -1,3 +1,6 @@
+#ifndef CONF_H
+#define CONF_H
+
 typedef struct ConfigEntry {
     char               *key;
     char               *value;
@@ -11,3 +14,5 @@ typedef struct {
 Config     *config_load(const char *filename);
 const char *config_get(Config *cfg, const char *key);
 void        config_free(Config *cfg);
+
+#endif // CONF_H
diff --git a/fir2.c b/fir2.c
index adcf30a..f2aa6e5 100644
--- a/fir2.c
+++ b/fir2.c
@@ -6,7 +6,7 @@
 
 /* This needs to be a power of two for the bitmask optimizations to work */
 /* If a non power of two length is desired, change to modulo */
-#define FIR_LEN (1u << 5)
+#define FIR_LEN (1u << 5) // = 32
 _Static_assert((FIR_LEN & (FIR_LEN - 1u)) == 0, "FIR_LEN must be a power of two");
 
 typedef struct {
diff --git a/winsz.c b/winsz.c
index 19d66fb..e57c63b 100644
--- a/winsz.c
+++ b/winsz.c
@@ -5,6 +5,10 @@
 int main(void) {
     struct winsize w;
 
+    /* See: man 2 ioctl */
+    /* See: man 2 TIOCGWINSZ */
+    /* See: linux/fs/ioctl.c */
+    /* See: linux/drivers/tty/tty_io.c (L: ~2709 and ~2359) */
     if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &w) == -1) {
         perror("ioctl");
         return 1;