diff --git a/examples/1-basic-backdoor/deconfound.py b/examples/1-basic-backdoor/deconfound.py
new file mode 100644
index 0000000..ae88152
--- /dev/null
+++ b/examples/1-basic-backdoor/deconfound.py
@@ -0,0 +1,22 @@
+from pathlib import Path
+
+from do import API, Expression, Intervention, Outcome
+
+api = API()
+
+file = Path("pearl-3.4.yml")
+model = api.instantiate_model(file)
+
+xj = Outcome("Xj", "xj")
+xi = Intervention("Xi", "xi")
+e = Expression(xj, [xi])
+
+# basic inference won't work!
+try:
+    api.probability(e, model)
+    print("This cannot happen!")
+
+except Exception:
+    e2 = Expression(xj)
+    result = api.treat(e2, [xi], model)
+    print(result)
diff --git a/examples/1-basic-backdoor/pearl-3.4.yml b/examples/1-basic-backdoor/pearl-3.4.yml
new file mode 100644
index 0000000..403319c
--- /dev/null
+++ b/examples/1-basic-backdoor/pearl-3.4.yml
@@ -0,0 +1,116 @@
+name: 'Pearl: Figure 3.4'
+endogenous:
+  X1:
+    outcomes:
+    - x1
+    - ~x1
+    parents: []
+    table: [
+      [x1, 0.4],
+      [~x1, 0.6]
+    ]
+  X2:
+    outcomes:
+    - x2
+    - ~x2
+    parents: []
+    table: [
+      [x2, 0.15],
+      [~x2, 0.85]
+    ]
+  X3:
+    outcomes:
+    - x3
+    - ~x3
+    parents:
+    - X1
+    table: [
+      [x3, x1, 0.1],
+      [x3, ~x1, 0.3],
+      [~x3, x1, 0.9],
+      [~x3, ~x1, 0.7]
+    ]
+  X4:
+    outcomes:
+    - x4
+    - ~x4
+    parents:
+    - X1
+    - X2
+    table: [
+      [x4, x1, x2, 0.7],
+      [x4, x1, ~x2, 0.9],
+      [x4, ~x1, x2, 0.55],
+      [x4, ~x1, ~x2, 0.15],
+      [~x4, x1, x2, 0.3],
+      [~x4, x1, ~x2, 0.1],
+      [~x4, ~x1, x2, 0.45],
+      [~x4, ~x1, ~x2, 0.85]
+   ]
+  X5:
+    outcomes:
+    - x5
+    - ~x5
+    parents:
+    - X2
+    table: [
+      [x5, x2, 0.8],
+      [x5, ~x2, 0.25],
+      [~x5, x2, 0.2],
+      [~x5, ~x2, 0.75]
+    ]
+  X6:
+    outcomes:
+    - x6
+    - ~x6
+    parents:
+    - Xi
+    table: [
+      [x6, xi, 0.9],
+      [x6, ~xi, 0.25],
+      [~x6, xi, 0.1],
+      [~x6, ~xi, 0.75]
+   ]
+  Xi:
+    outcomes:
+    - xi
+    - ~xi
+    parents:
+    - X3
+    - X4
+    table: [
+      [xi, x3, x4, 0.5],
+      [xi, x3, ~x4, 0.65],
+      [xi, ~x3, x4, 0.1],
+      [xi, ~x3, ~x4, 0.25],
+      [~xi, x3, x4, 0.5],
+      [~xi, x3, ~x4, 0.35],
+      [~xi, ~x3, x4, 0.9],
+      [~xi, ~x3, ~x4, 0.75]
+    ]
+  Xj:
+    outcomes:
+    - xj
+    - ~xj
+    parents:
+    - X6
+    - X4
+    - X5
+    table: [
+      [xj, x6, x4, x5, 0.0],
+      [xj, x6, x4, ~x5, 0.25],
+      [xj, x6, ~x4, x5, 0.7],
+      [xj, x6, ~x4, ~x5, 0.45],
+      [xj, ~x6, x4, x5, 0.15],
+      [xj, ~x6, x4, ~x5, 0.8],
+      [xj, ~x6, ~x4, x5, 0.95],
+      [xj, ~x6, ~x4, ~x5, 0.05],
+      [~xj, x6, x4, x5, 1.0],
+      [~xj, x6, x4, ~x5, 0.75],
+      [~xj, x6, ~x4, x5, 0.3],
+      [~xj, x6, ~x4, ~x5, 0.55],
+      [~xj, ~x6, x4, x5, 0.85],
+      [~xj, ~x6, x4, ~x5, 0.2],
+      [~xj, ~x6, ~x4, x5, 0.05],
+      [~xj, ~x6, ~x4, ~x5, 0.95]
+    ]