diff --git a/cbase/Makefile b/cbase/Makefile
new file mode 100644
index 0000000..661c5b5
--- /dev/null
+++ b/cbase/Makefile
@@ -0,0 +1,5 @@
+test:
+	cd data/ && $(MAKE) test
+	cd algo/ && $(MAKE) test
+
+.PHONY: test
diff --git a/cbase/data/Makefile b/cbase/data/Makefile
new file mode 100644
index 0000000..e69de29
diff --git a/cbase/data/lists/Makefile b/cbase/data/lists/Makefile
new file mode 100644
index 0000000..d3f1fe6
--- /dev/null
+++ b/cbase/data/lists/Makefile
@@ -0,0 +1,26 @@
+OBJ=linkedlist.o
+SRC=$(OBJ:.o=.c)
+HDR=$(SRC:.c=.h)
+TST=$(SRC:.c=.test.c)
+TSTBIN=$(TST:.test.c=.test)
+
+CFLAGS+=-Wall
+CFLAGS+=-Wextra
+
+all: $(OBJ)
+
+.PHONY: all
+
+test: $(TSTBIN)
+
+.PHONY: test
+
+clean:
+	$(RM) $(OBJ) $(TSTBIN)
+
+%.o: %.c %.h
+	$(CC) -o $@ -c $< $(CFLAGS)
+
+$(TSTBIN): $(TST) $(OBJ)
+	$(CC) -o $@ $(@:=.c) $(@:.test=.c) $(CFLAGS)
+	./$@
diff --git a/cbase/data/lists/linkedlist.c b/cbase/data/lists/linkedlist.c
new file mode 100644
index 0000000..0ee1e9b
--- /dev/null
+++ b/cbase/data/lists/linkedlist.c
@@ -0,0 +1,116 @@
+#include <stdlib.h>
+
+#include "linkedlist.h"
+
+LinkedList*
+new_linkedlist() {
+	// TODO: handle malloc failure
+	LinkedListNode* nil = malloc(sizeof(LinkedListNode));
+	nil->next = nil;
+	nil->prev = nil;
+
+	LinkedList* l = malloc(sizeof(LinkedList));
+	l->nil = nil;
+
+	return l;
+}
+
+LinkedListNode*
+first(LinkedList* l) {
+	return l->nil->next;
+}
+
+LinkedListNode*
+last(LinkedList* l) {
+	return l->nil->prev;
+}
+
+void
+append(LinkedList* l, void* x) {
+	LinkedListNode* nil = l->nil;
+
+	// TODO: handle malloc failure
+	LinkedListNode* y = malloc(sizeof(LinkedListNode));
+	y->next = nil;
+	y->prev = nil->prev->prev;
+	y->data = x;
+
+	nil->prev->prev->next = y;
+	nil->prev = y;
+}
+
+void
+insert(LinkedList* l, void* x) {
+	LinkedListNode* nil = l->nil;
+
+	// TODO: handle malloc failure
+	LinkedListNode* y = malloc(sizeof(LinkedListNode));
+	y->prev = nil;
+	y->next = nil->next;
+	y->data = x;
+
+	nil->next->prev = x;
+	nil->next = x;
+}
+
+void
+insert_at(LinkedList* l, int at, void* x) {
+	LinkedListNode* nil = l->nil;
+	LinkedListNode* y = nil;
+
+	for (int i = 0; i < at; i++) {
+		y = y->next;
+		if (y == nil) {
+			// Index out of range
+		}
+	}
+
+	// TODO: handle malloc failure
+	LinkedListNode* new = malloc(sizeof(LinkedListNode));
+	new->prev = y;
+	new->next = y->next;
+	new->data = x;
+
+	y->next->prev = new;
+	y->next = new;
+}
+
+LinkedListNode*
+search(LinkedList* l, void* x) {
+	LinkedListNode* y = l->nil->next;
+
+	while (y != l->nil) {
+		if (y->data == x)
+			return y;
+		y = y->next;
+	}
+
+	return NULL;
+}
+
+void
+delete_item(LinkedListNode* x) {
+	x->prev->next = x->next;
+	x->next->prev = x->prev;
+
+	free(x);
+}
+
+void
+delete_linkedlist(LinkedList* l) {
+	free(l->nil);
+	free(l);
+}
+
+int
+count_linkedlist(LinkedList* l) {
+	int n = 0;
+	LinkedListNode* x = l->nil;
+
+	while (x->next != l->nil) {
+		x = x->next;
+		n++;
+	}
+
+	return n;
+}
diff --git a/cbase/data/lists/linkedlist.h b/cbase/data/lists/linkedlist.h
new file mode 100644
index 0000000..0ae3b7a
--- /dev/null
+++ b/cbase/data/lists/linkedlist.h
@@ -0,0 +1,44 @@
+#ifndef LINKEDLIST_H
+#define LINKEDLIST_H
+
+typedef struct LinkedListNode {
+	void* data;
+	struct LinkedListNode* prev;
+	struct LinkedListNode* next;
+} LinkedListNode;
+
+typedef struct LinkedList {
+	LinkedListNode* nil;
+} LinkedList;
+
+LinkedList*
+new_linkedlist();
+
+LinkedListNode*
+first(LinkedList* l);
+
+LinkedListNode*
+last(LinkedList* l);
+
+void
+append(LinkedList* l, void* x);
+
+void
+insert(LinkedList* l, void* x);
+
+void
+insert_at(LinkedList* l, int i, void* x);
+
+LinkedListNode*
+search(LinkedList* l, void* x);
+
+void
+delete_item(LinkedListNode* x);
+
+void
+delete_linkedlist(LinkedList* l);
+
+int
+count_linkedlist(LinkedList* l);
+
+#endif
diff --git a/cbase/data/lists/linkedlist.test b/cbase/data/lists/linkedlist.test
new file mode 100755
index 0000000..e914660
Binary files /dev/null and b/cbase/data/lists/linkedlist.test differ
diff --git a/cbase/data/lists/linkedlist.test.c b/cbase/data/lists/linkedlist.test.c
new file mode 100644
index 0000000..3da5d15
--- /dev/null
+++ b/cbase/data/lists/linkedlist.test.c
@@ -0,0 +1,35 @@
+#include<stdio.h>
+#include<assert.h>
+
+#include "linkedlist.h"
+
+void
+test_empty() {
+	LinkedList* l = new_linkedlist();
+	assert(count_linkedlist(l) == 0);
+	delete_linkedlist(l);
+}
+
+void
+test_single() {
+	LinkedList* l = new_linkedlist();
+
+	int x = 42;
+	int* p = &x;
+
+	append(l, p);
+	assert(count_linkedlist(l) == 1);
+	assert(first(l)->data == p);
+	assert(last(l)->data == p);
+
+	delete_item(first(l));
+	assert(count_linkedlist(l) == 0);
+
+	delete_linkedlist(l);
+}
+
+int
+main() {
+	test_empty();
+	test_single();
+}
diff --git a/cbase/data/stack.c b/cbase/data/stack.c
new file mode 100644
index 0000000..e69de29
diff --git a/cbase/data/stack.h b/cbase/data/stack.h
new file mode 100644
index 0000000..e69de29
diff --git a/cbase/data/trees/Makefile b/cbase/data/trees/Makefile
new file mode 100644
index 0000000..5fa6ca5
--- /dev/null
+++ b/cbase/data/trees/Makefile
@@ -0,0 +1,14 @@
+OBJ=binarytree.o bst.o rbtree.o
+SRC=$(OBJ:.o=.c)
+HDR=$(SRC:.c=.h)
+
+CFLAGS+=-Wall
+CFLAGS+=-Wextra
+
+all: $(OBJ)
+
+clean:
+	$(RM) $(OBJ)
+
+%.o: %.c %.h
+	$(CC) -o $@ -c $< $(CFLAGS)
diff --git a/cbase/data/trees/binarytree.c b/cbase/data/trees/binarytree.c
new file mode 100644
index 0000000..17db9c5
--- /dev/null
+++ b/cbase/data/trees/binarytree.c
@@ -0,0 +1 @@
+#include "binarytree.h"
\ No newline at end of file
diff --git a/cbase/data/trees/binarytree.h b/cbase/data/trees/binarytree.h
new file mode 100644
index 0000000..46544b8
--- /dev/null
+++ b/cbase/data/trees/binarytree.h
@@ -0,0 +1,13 @@
+#ifndef BINARYTREE_H
+#define BINARYTREE_H
+
+typedef struct BinaryTreeNode {
+	void* data;
+	struct BinaryTreeNode* left;
+	struct BinaryTreeNode* right;
+} BinaryTreeNode;
+
+BinaryTreeNode*
+new_binarytree();
+
+#endif
diff --git a/cbase/data/trees/bst.c b/cbase/data/trees/bst.c
new file mode 100644
index 0000000..26be7d9
--- /dev/null
+++ b/cbase/data/trees/bst.c
@@ -0,0 +1 @@
+#include "bst.h"
\ No newline at end of file
diff --git a/cbase/data/trees/bst.h b/cbase/data/trees/bst.h
new file mode 100644
index 0000000..924aeb8
--- /dev/null
+++ b/cbase/data/trees/bst.h
@@ -0,0 +1,5 @@
+#ifndef BST_H
+#define BST_H
+
+
+#endif
diff --git a/cbase/data/trees/rbtree.c b/cbase/data/trees/rbtree.c
new file mode 100644
index 0000000..16f8cac
--- /dev/null
+++ b/cbase/data/trees/rbtree.c
@@ -0,0 +1 @@
+#include "rbtree.h"
\ No newline at end of file
diff --git a/cbase/data/trees/rbtree.h b/cbase/data/trees/rbtree.h
new file mode 100644
index 0000000..a1b6d9e
--- /dev/null
+++ b/cbase/data/trees/rbtree.h
@@ -0,0 +1,16 @@
+#ifndef RBTREE_H
+#define RBTREE_H
+
+typedef enum {
+	Red,
+	Black,
+} RBColor;
+
+typedef struct RBTreeNode {
+	void* data;
+	struct RBTreeNode* left;
+	struct RBTreeNode* right;
+	RBColor color;
+} RBTreeNode;
+
+#endif