diff --git a/README.md b/README.md
index 151f053d..c86331ec 100644
--- a/README.md
+++ b/README.md
@@ -191,7 +191,7 @@ tinygrad will always be below 1000 lines. If it isn't, we will revert commits un
 
 ```bash
 GRAPH=1 python3 test/test_mnist.py TestMNIST.test_sgd_onestep
-dot -Tsvg /tmp/net.dot -o /tmp/net.svg && open /tmp/net.svg
+# requires dot, outputs /tmp/net.svg
 ```
 
 ### Running tests
diff --git a/test/test_conv.py b/test/test_conv.py
index 7c6239d9..35b02141 100644
--- a/test/test_conv.py
+++ b/test/test_conv.py
@@ -45,5 +45,14 @@ class TestConv(unittest.TestCase):
     w = Tensor.ones(32,1,3,3)
     x = x.conv2d(w, padding=(1,1), groups=32)
 
+  def test_bias(self):
+    from tinygrad.nn import Conv2d
+    x = Tensor.ones(1,12,128,256)
+    c = Conv2d(12, 32, 3)
+    x = c(x)
+    x = x.relu()
+    w = Tensor.uniform(32, 1, 3, 3)
+    x = x.conv2d(w, groups=32)
+
 if __name__ == '__main__':
   unittest.main()
\ No newline at end of file
diff --git a/tinygrad/ops.py b/tinygrad/ops.py
index 875b6103..45301b21 100644
--- a/tinygrad/ops.py
+++ b/tinygrad/ops.py
@@ -18,6 +18,7 @@ if GRAPH:
   def save_graph_exit():
     print("saving", G)
     nx.drawing.nx_pydot.write_dot(G, '/tmp/net.dot')
+    os.system('dot -Tsvg /tmp/net.dot -o /tmp/net.svg')
   atexit.register(save_graph_exit)
 
 global_num_max = 0
diff --git a/tinygrad/shapetracker.py b/tinygrad/shapetracker.py
index 9adbf693..7c9f82f4 100644
--- a/tinygrad/shapetracker.py
+++ b/tinygrad/shapetracker.py
@@ -73,40 +73,48 @@ class ShapeTracker:
   def reshape(self, *new_shape):
     assert all([isinstance(x, int) for x in new_shape])
     assert prod(self.shape) == prod(new_shape)
+    if self.shape == new_shape: return
     self.views.append(View(new_shape, strides_for_shape(new_shape)))
 
   def permute(self, *axis):
-    self.contiguous = False
     assert all([isinstance(x, int) and x >= 0 and x < len(self.shape) for x in axis])
     assert len(set(axis)) == len(axis) and len(axis) == len(self.shape)
+    if tuple(range(len(axis))) == axis: return
+    self.contiguous = False
     strides = strides_for_shape(self.shape)
     self.views.append(View([self.shape[a] for a in axis], [strides[a] for a in axis]))
 
+  # TODO: this is a special case of slice with strides, remove it
+  # though it's nice that it can't change size
+  def flip(self, *axis):
+    self.stride(*[-1 if i in axis else 1 for i in range(len((self.shape)))])
+
+  # *** under this line are not invertible ***
+
   def slice(self, *arg):
-    self.contiguous = False
     assert len(arg) == len(self.shape)
+    if all([(x,y) == (0,s) for s,(x,y) in zip(self.shape, arg)]): return
+    self.contiguous = False
     strides = strides_for_shape(self.shape)
     offset = sum([strides[i]*x for i,(x,_) in enumerate(arg)])
     self.views += [View([y-x for x,y in arg], strides, offset), ZeroView(self.shape, arg)]
 
   def expand(self, *new_shape):
-    self.contiguous = False
     assert all([isinstance(x, int) for x in new_shape])
     assert all([x == y or x == 1 for x,y in zip(self.shape, new_shape)])
+    if self.shape == new_shape: return
+    self.contiguous = False
     strides = [s if x == y else 0 for s,(x,y) in zip(strides_for_shape(self.shape), zip(self.shape, new_shape))]
     self.views.append(View(new_shape, strides))
 
   # TODO: combine with slice? this doesn't require a ZeroView, though slice shouldn't always either
   def stride(self, *mul):
-    self.contiguous = False
     assert all([isinstance(x, int) for x in mul])
+    if all([x==1 for x in mul]): return
+    self.contiguous = False
     old_strides = strides_for_shape(self.shape)
     strides = [z*m for z,m in zip(old_strides, mul)]
     new_shape = [(s+(abs(m)-1))//abs(m) for s,m in zip(self.shape, mul)]
     offset = sum([(s-1)*z for s,z,m in zip(self.shape,old_strides,mul) if m < 0])
     self.views.append(View(new_shape, strides, offset))
 
-  # TODO: this is a special case of slice with strides, remove it
-  # though it's nice that it can't change size
-  def flip(self, *axis):
-    self.stride(*[-1 if i in axis else 1 for i in range(len((self.shape)))])