diff --git a/include/nodes.h b/include/nodes.h
index 6349209..93dc072 100644
--- a/include/nodes.h
+++ b/include/nodes.h
@@ -1,6 +1,7 @@
 #ifndef NODES_H
 #define NODES_H
 
+#include "aliases/aliases.h"
 #include "window.h"
 
 #define MAX_NODES 1024
@@ -13,20 +14,27 @@
 #define OP_NODE_FILL_COLOUR ((colour_t){.abgr = 0xffad6c3a})
 #define OP_NODE_BORDER_COLOUR ((colour_t){.abgr = 0xff8e4a33})
 
+typedef i32 (*node_func_t)(i32 a, i32 b);
+typedef enum node_type node_type_t;
+typedef union node_data node_data_t;
 typedef struct node node_t;
 
-enum comp_ops {
-  COMP_OP_ADD,
-  COMP_OP_SUB,
-  COMP_OP_MUL,
-  COMP_OP_DIV,
+enum node_type {
+  NODE_TYPE_IO,
+  NODE_TYPE_OP,
 
-  COUNT_COMP_OPS,
+  COUNT_NODE_TYPES,
+};
+
+union node_data {
+  const char *path;
+  node_func_t func;
 };
 
 struct node {
   rect_t rect;
-  const char *path;
+  node_type_t type;
+  node_data_t data;
 };
 
 bool aabb(const node_t *node, i32 x, i32 y);
diff --git a/src/nodes.c b/src/nodes.c
index a99de33..d73309c 100644
--- a/src/nodes.c
+++ b/src/nodes.c
@@ -1,13 +1,33 @@
 #include "nodes.h"
 #include "aliases/aliases.h"
+#include "window.h"
 #include <stdbool.h>
 
+typedef struct node_colours node_colours_t;
+struct node_colours {
+  colour_t fill;
+  colour_t border;
+};
+
+INTERNAL node_colours_t colours[COUNT_NODE_TYPES] = {
+    [NODE_TYPE_IO] =
+        (node_colours_t){
+            .fill = IO_NODE_FILL_COLOUR,
+            .border = IO_NODE_BORDER_COLOUR,
+        },
+    [NODE_TYPE_OP] =
+        (node_colours_t){
+            .fill = OP_NODE_FILL_COLOUR,
+            .border = OP_NODE_BORDER_COLOUR,
+        },
+};
+
 bool aabb(const node_t *node, i32 x, i32 y) {
   return x > node->rect.topleft.x && x <= node->rect.topleft.x + node->rect.w &&
          y > node->rect.topleft.y && y <= node->rect.topleft.y + node->rect.h;
 }
 
 void draw_node(const window_t *wnd, const node_t *node) {
-  fill_rect(wnd, &(node->rect), IO_NODE_FILL_COLOUR);
-  draw_rect(wnd, &(node->rect), IO_NODE_BORDER_COLOUR);
+  fill_rect(wnd, &(node->rect), colours[node->type].fill);
+  draw_rect(wnd, &(node->rect), colours[node->type].border);
 }