diff --git a/test/test_linearizer.py b/test/test_linearizer.py
index 8faf467dbb..e0dd59f734 100644
--- a/test/test_linearizer.py
+++ b/test/test_linearizer.py
@@ -902,7 +902,8 @@ class TestLinearizer(unittest.TestCase):
     lin = helper_linearizer_opt(out, wanna_output=[a.numpy().sum()*a.numpy().sum()])[0]
     # RANGE -> LOAD -> ASSIGN -> ALU
     end = max(i for i,u in enumerate(lin.uops) if u.op is Ops.ENDRANGE)
-    assert lin.uops[end+1].op in GroupOp.ALU
+    # the INDEX can be first
+    assert lin.uops[end+1].op in GroupOp.ALU or lin.uops[end+2].op in GroupOp.ALU
 
   def test_range_outer_op_after_phi_nested_range(self):
     a = Tensor.randn(2, ).realize()
@@ -910,7 +911,8 @@ class TestLinearizer(unittest.TestCase):
     lin = helper_linearizer_opt(out, wanna_output=[(np.broadcast_to(a.numpy().reshape(2, 1), (2, 3))).sum()*2])[0]
     # RANGE -> LOAD -> ASSIGN -> ALU
     end = max(i for i,u in enumerate(lin.uops) if u.op is Ops.ENDRANGE)
-    assert lin.uops[end+1].op in GroupOp.ALU
+    # the INDEX can be first
+    assert lin.uops[end+1].op in GroupOp.ALU or lin.uops[end+2].op in GroupOp.ALU
 
   def test_load_dedup(self):
     # for different leaves in the AST, the same loads may occur.
diff --git a/test/test_uops.py b/test/test_uops.py
index 53060f44a1..85896bf82b 100644
--- a/test/test_uops.py
+++ b/test/test_uops.py
@@ -336,8 +336,9 @@ class TestAssembly(unittest.TestCase):
     a2 = UOp(Ops.MUL, dtypes.int, (l1, c2))
     uops = to_uops_list([a1,a2], opts=Device[Device.DEFAULT].renderer)
     Device[Device.DEFAULT].renderer.render("test", uops)
-    self.assertEqual(uops[-1].op, Ops.SHL)
-    self.assertEqual(uops[-2].op, Ops.MUL)
+    ops = [x.op for x in uops]
+    self.assertIn(Ops.SHL, ops)
+    self.assertIn(Ops.MUL, ops)
 
   def test_bitshift_right(self):
     g1 = UOp(Ops.DEFINE_GLOBAL, dtypes.int32.ptr(), (), 0)
@@ -348,8 +349,9 @@ class TestAssembly(unittest.TestCase):
     a2 = UOp(Ops.IDIV, dtypes.int, (l1, c2))
     uops = to_uops_list([a1,a2], opts=Device[Device.DEFAULT].renderer)
     Device[Device.DEFAULT].renderer.render("test", uops)
-    self.assertEqual(uops[-1].op, Ops.SHR)
-    self.assertEqual(uops[-2].op, Ops.IDIV)
+    ops = [x.op for x in uops]
+    self.assertIn(Ops.SHR, ops)
+    self.assertIn(Ops.IDIV, ops)
 
 class TestUOpMethod(unittest.TestCase):
   @unittest.skip("uops lt no longer ordered")
diff --git a/tinygrad/ops.py b/tinygrad/ops.py
index e091371b28..f19b50536f 100644
--- a/tinygrad/ops.py
+++ b/tinygrad/ops.py
@@ -107,6 +107,9 @@ class Ops(FastEnum):
   EMPTY = auto()
   BUFFER_VIEW = auto()
 
+  # blocks in linearizer
+  BLOCK = auto(); BLOCKSTART = auto(); BLOCKFORK = auto(); BLOCKEND = auto()  # noqa: E702
+
   EXPAND = auto()
   CONTRACT = auto()
   VIEW = auto()
diff --git a/tinygrad/viz/serve.py b/tinygrad/viz/serve.py
index 6b4bd8b7a4..2d93b4ced4 100755
--- a/tinygrad/viz/serve.py
+++ b/tinygrad/viz/serve.py
@@ -11,7 +11,8 @@ from tinygrad.codegen.kernel import Kernel
 uops_colors = {Ops.LOAD: "#ffc0c0", Ops.PRELOAD: "#ffc0c0", Ops.STORE: "#87CEEB", Ops.CONST: "#e0e0e0", Ops.VCONST: "#e0e0e0",
                Ops.DEFINE_GLOBAL: "#ffe0b0", Ops.DEFINE_LOCAL: "#ffe0d0", Ops.DEFINE_ACC: "#f0ffe0", Ops.REDUCE_AXIS: "#FF6B6B",
                Ops.RANGE: "#c8a0e0", Ops.ASSIGN: "#e0ffc0", Ops.BARRIER: "#ff8080", Ops.IF: "#c8b0c0", Ops.SPECIAL: "#c0c0ff",
-               Ops.INDEX: "#e8ffa0", Ops.WMMA: "#efefc0", Ops.VIEW: "#C8F9D4", **{x:"#ffffc0" for x in GroupOp.ALU}, Ops.BUFFER: "#B0BDFF",}
+               Ops.INDEX: "#e8ffa0", Ops.WMMA: "#efefc0", Ops.VIEW: "#C8F9D4", **{x:"#ffffc0" for x in GroupOp.ALU},
+               Ops.BLOCK: "#C4A484", Ops.BLOCKEND: "#C4A4A4", Ops.BUFFER: "#B0BDFF",}
 
 # ** API spec