This is from Sanjoy Mahajan's The Art of Insight Problem 1.5

Make a tree diagram for your estimate in Problem 1.3. Do it in three steps: (1) Draw the tree without any leaf estimates, (2) estimate the leaf values, and (3) propagate the leaf values upward to the root.

This is referring to the suitcase of money.

# Step 1: Tree

graph LR;
VolBankNote[Volume of Bank Note]
VolSuitcase[Volume of Suitcase]
ValueBankNote[Value of Bank Notes in Suitcase]
NumBankNote[Number of Bank Notes in Suitcase]
ValueSuitcase[Value of Suitcase]
NumBankNote --> ValueSuitcase
ValueBankNote --> ValueSuitcase
VolBankNote -->|-1| NumBankNote
VolSuitcase --> NumBankNote
SuitWidth[Width of Suitcase] --> VolSuitcase
SuitHeight[Height of Suitcase] --> VolSuitcase
SuitDepth[Depth of Suitcase] --> VolSuitcase
BankHeight[Height of Bank Note] --> VolBankNote
BankWidth[Width of Bank Note] --> VolBankNote
BankDepth[Thickness of Bank Note] --> VolBankNote

# Step 2: Annotated Leaves

graph LR;
VolBankNote[Volume of Bank Note]
VolSuitcase[Volume of Suitcase]
ValueBankNote[Value of Bank Notes in Suitcase

$100] NumBankNote[Number of Bank Notes in Suitcase] ValueSuitcase[Value of Suitcase] NumBankNote --> ValueSuitcase ValueBankNote --> ValueSuitcase VolBankNote -->|-1| NumBankNote VolSuitcase --> NumBankNote SuitWidth[Width of Suitcase

30cm] --> VolSuitcase SuitHeight[Height of Suitcase

50cm] --> VolSuitcase SuitDepth[Depth of Suitcase

30cm] --> VolSuitcase BankHeight[Height of Bank Note

15cm] --> VolBankNote BankWidth[Width of Bank Note

6cm] --> VolBankNote BankDepth[Thickness of Bank Note

0.01cm] --> VolBankNote

$100] NumBankNote[Number of Bank Notes in Suitcase] ValueSuitcase[Value of Suitcase] NumBankNote --> ValueSuitcase ValueBankNote --> ValueSuitcase VolBankNote -->|-1| NumBankNote VolSuitcase --> NumBankNote SuitWidth[Width of Suitcase

30cm] --> VolSuitcase SuitHeight[Height of Suitcase

50cm] --> VolSuitcase SuitDepth[Depth of Suitcase

30cm] --> VolSuitcase BankHeight[Height of Bank Note

15cm] --> VolBankNote BankWidth[Width of Bank Note

6cm] --> VolBankNote BankDepth[Thickness of Bank Note

0.01cm] --> VolBankNote

# Step 3: Propagate

graph LR;
VolBankNote[Volume of Bank Note

1 cm

50L] ValueBankNote[Value of Bank Notes in Suitcase

$100] NumBankNote[Number of Bank Notes in Suitcase

50,000] ValueSuitcase[Value of Suitcase

$5 Million] NumBankNote --> ValueSuitcase ValueBankNote --> ValueSuitcase VolBankNote -->|-1| NumBankNote VolSuitcase --> NumBankNote SuitWidth[Width of Suitcase

30cm] --> VolSuitcase SuitHeight[Height of Suitcase

50cm] --> VolSuitcase SuitDepth[Depth of Suitcase

30cm] --> VolSuitcase BankHeight[Height of Bank Note

15cm] --> VolBankNote BankWidth[Width of Bank Note

6cm] --> VolBankNote BankDepth[Thickness of Bank Note

0.01cm] --> VolBankNote

1 cm

^{3}] VolSuitcase[Volume of Suitcase50L] ValueBankNote[Value of Bank Notes in Suitcase

$100] NumBankNote[Number of Bank Notes in Suitcase

50,000] ValueSuitcase[Value of Suitcase

$5 Million] NumBankNote --> ValueSuitcase ValueBankNote --> ValueSuitcase VolBankNote -->|-1| NumBankNote VolSuitcase --> NumBankNote SuitWidth[Width of Suitcase

30cm] --> VolSuitcase SuitHeight[Height of Suitcase

50cm] --> VolSuitcase SuitDepth[Depth of Suitcase

30cm] --> VolSuitcase BankHeight[Height of Bank Note

15cm] --> VolBankNote BankWidth[Width of Bank Note

6cm] --> VolBankNote BankDepth[Thickness of Bank Note

0.01cm] --> VolBankNote