diff --git a/benchmark/01-factorial.scm b/benchmark/01-factorial.scm
new file mode 100644
index 0000000..ff86756
--- /dev/null
+++ b/benchmark/01-factorial.scm
@@ -0,0 +1,5 @@
+(letrec ((fact (lambda (n acc)
+                 (if (< n 2)
+                     acc
+                     (fact (- n 1) (* n acc))))))
+  (fact 20 1))
diff --git a/benchmark/01-fib31.scm b/benchmark/01-fib31.scm
deleted file mode 100644
index 8db51c1..0000000
--- a/benchmark/01-fib31.scm
+++ /dev/null
@@ -1,5 +0,0 @@
-(letrec ((fib (lambda (n)
-                (if (< n 2)
-                    n
-                    (+ (fib (- n 1)) (fib (- n 2)))))))
-  (fib 31))
diff --git a/benchmark/02-dotproduct.scm b/benchmark/02-dotproduct.scm
new file mode 100644
index 0000000..c70bf7a
--- /dev/null
+++ b/benchmark/02-dotproduct.scm
@@ -0,0 +1,9 @@
+(let ((v1 (make-vector 4000000 1))
+      (v2 (make-vector 4000000 2)))
+  (letrec ((dot (lambda (i acc)
+                  (if (= i 4000000)
+                      acc
+                      (dot (+ i 1)
+                           (+ acc (* (vector-ref v1 i)
+                                     (vector-ref v2 i))))))))
+    (dot 0 0)))
diff --git a/benchmark/02-fib30.scm b/benchmark/02-fib30.scm
deleted file mode 100644
index 1e7975f..0000000
--- a/benchmark/02-fib30.scm
+++ /dev/null
@@ -1,5 +0,0 @@
-(letrec ((fib (lambda (n)
-                (if (< n 2)
-                    n
-                    (+ (fib (- n 1)) (fib (- n 2)))))))
-  (fib 30))
diff --git a/benchmark/03-loop2_5.scm b/benchmark/03-loop2_5.scm
deleted file mode 100644
index d7c3ad3..0000000
--- a/benchmark/03-loop2_5.scm
+++ /dev/null
@@ -1,5 +0,0 @@
-(letrec ((loop (lambda (n acc)
-                (if (< n 2500000)
-                    (loop (+ n 1) (+ acc n))
-                    acc))))
-  (loop 0 0))
diff --git a/benchmark/03-nbody.scm b/benchmark/03-nbody.scm
new file mode 100644
index 0000000..d1ec810
--- /dev/null
+++ b/benchmark/03-nbody.scm
@@ -0,0 +1,23 @@
+(letrec
+  ((iterate (lambda (x1 y1 vx1 vy1 x2 y2 vx2 vy2 steps)
+              (if (= steps 0)
+                  (+ x1 x2)
+                  (let ((dx (- x2 x1))
+                        (dy (- y2 y1)))
+                    (let ((d2 (+ (* dx dx) (* dy dy))))
+                      (let ((f (/ 1 d2)))
+                        (let ((ax (* f dx))
+                              (ay (* f dy)))
+                          (let ((bx (- ax))
+                                (by (- ay)))
+                            (iterate (+ x1 vx1)
+                                     (+ y1 vy1)
+                                     (+ vx1 ax)
+                                     (+ vy1 ay)
+                                     (+ x2 vx2)
+                                     (+ y2 vy2)
+                                     (+ vx2 bx)
+                                     (+ vy2 by)
+                                     (- steps 1))))))))))
+  )
+  (iterate 0 0 0 1 1 0 0 -1 1000000))
diff --git a/benchmark/04-bst.scm b/benchmark/04-bst.scm
new file mode 100644
index 0000000..68c0051
--- /dev/null
+++ b/benchmark/04-bst.scm
@@ -0,0 +1,26 @@
+(letrec ((make-node (lambda (v l r) (cons v (cons l r))))
+         (left (lambda (node) (car (cdr node))))
+         (right (lambda (node) (cdr (cdr node))))
+         (insert (lambda (tree n)
+                   (if (null? tree)
+                       (make-node n '() '())
+                       (let ((v (car tree)))
+                         (if (< n v)
+                             (make-node v
+                                        (insert (left tree) n)
+                                        (right tree))
+                             (make-node v
+                                        (left tree)
+                                        (insert (right tree) n))))))
+         )
+         (build (lambda (i max tree)
+                  (if (= i max)
+                      tree
+                      (build (+ i 1) max (insert tree i)))))
+         (sum-tree (lambda (tree)
+                     (if (null? tree)
+                         0
+                         (+ (car tree)
+                            (sum-tree (left tree))
+                            (sum-tree (right tree)))))))
+  (sum-tree (build 0 2200 '())))
diff --git a/benchmark/04-loop3.scm b/benchmark/04-loop3.scm
deleted file mode 100644
index 0a01425..0000000
--- a/benchmark/04-loop3.scm
+++ /dev/null
@@ -1,5 +0,0 @@
-(letrec ((loop (lambda (n acc)
-                (if (< n 3500000)
-                    (loop (+ n 1) (+ acc n))
-                    acc))))
-  (loop 0 0))
diff --git a/benchmark/05-loop5.scm b/benchmark/05-loop5.scm
deleted file mode 100644
index cf16df3..0000000
--- a/benchmark/05-loop5.scm
+++ /dev/null
@@ -1,5 +0,0 @@
-(letrec ((loop (lambda (n acc)
-                (if (< n 5000000)
-                    (loop (+ n 1) (+ acc n))
-                    acc))))
-  (loop 0 0))
diff --git a/benchmark/run.ts b/benchmark/run.ts
index 926e963..d851758 100644
--- a/benchmark/run.ts
+++ b/benchmark/run.ts
@@ -3,26 +3,39 @@ import path from 'path';
 import * as FoxScheme from '../src/foxscheme';
 
 const { Parser, Interpreter } = FoxScheme as any;
-const benchmarks = [
-  '01-fib31.scm',
-  '02-fib30.scm',
-  '03-loop2_5.scm',
-  '04-loop3.scm',
-  '05-loop5.scm'
+interface Benchmark {
+  file: string;
+  expected: number;
+}
+
+const benchmarks: Benchmark[] = [
+  { file: '01-factorial.scm', expected: 2432902008176640000 },
+  { file: '02-dotproduct.scm', expected: 8000000 },
+  { file: '03-nbody.scm', expected: 1 },
+  { file: '04-bst.scm', expected: 2418900 },
 ];
 
 const interp = new Interpreter();
 let total = 0;
-for (const file of benchmarks) {
-  const code = fs.readFileSync(path.join(__dirname, file), 'utf8');
+for (const bench of benchmarks) {
+  const code = fs.readFileSync(path.join(__dirname, bench.file), 'utf8');
   const parser = new Parser(code);
   let obj: any;
+  let result: any = undefined;
   const start = Date.now();
   while ((obj = parser.nextObject()) !== Parser.EOS) {
-    interp.eval(obj);
+    result = interp.eval(obj);
   }
   const elapsed = Date.now() - start;
+  if (typeof result === 'number') {
+    const diff = Math.abs(result - bench.expected);
+    if (diff > 1e-9) {
+      throw new Error(`${bench.file} expected ${bench.expected} but got ${result}`);
+    }
+  } else if (result != bench.expected) {
+    throw new Error(`${bench.file} expected ${bench.expected} but got ${result}`);
+  }
   total += elapsed;
-  console.log(`${file}: ${ (elapsed/1000).toFixed(3) }s`);
+  console.log(`${bench.file}: ${(elapsed / 1000).toFixed(3)}s`);
 }
-console.log(`Total: ${(total/1000).toFixed(3)}s`);
+console.log(`Total: ${(total / 1000).toFixed(3)}s`);