diff --git a/src/witness_generator/generator.rs b/src/witness_generator/generator.rs
index b8549290b..72cc3a038 100644
--- a/src/witness_generator/generator.rs
+++ b/src/witness_generator/generator.rs
@@ -9,7 +9,7 @@ use super::affine_expression::AffineExpression;
 use super::bit_constraints::{BitConstraint, BitConstraintSet};
 use super::eval_error::EvalError;
 use super::expression_evaluator::{ExpressionEvaluator, SymbolicVariables};
-use super::machine::Machine;
+use super::machines::Machine;
 use super::util::contains_next_witness_ref;
 use super::{Constraint, EvalResult, FixedData, WitnessColumn};
 
diff --git a/src/witness_generator/double_sorted_witness_machine.rs b/src/witness_generator/machines/double_sorted_witness_machine.rs
similarity index 97%
rename from src/witness_generator/double_sorted_witness_machine.rs
rename to src/witness_generator/machines/double_sorted_witness_machine.rs
index da95f5ff3..ada46f54d 100644
--- a/src/witness_generator/double_sorted_witness_machine.rs
+++ b/src/witness_generator/machines/double_sorted_witness_machine.rs
@@ -3,15 +3,15 @@ use std::iter::once;
 
 use itertools::{Either, Itertools};
 
+use super::Machine;
 use crate::analyzer::PolynomialReference;
 use crate::analyzer::{Expression, Identity, IdentityKind, SelectedExpressions};
 use crate::number::AbstractNumberType;
-use crate::witness_generator::eval_error;
-
-use super::affine_expression::AffineExpression;
-use super::eval_error::EvalError;
-use super::machine::Machine;
-use super::{EvalResult, FixedData};
+use crate::witness_generator::{
+    affine_expression::AffineExpression,
+    eval_error::{self, EvalError},
+    EvalResult, FixedData,
+};
 
 /// TODO make this generic
 
diff --git a/src/witness_generator/fixed_lookup_machine.rs b/src/witness_generator/machines/fixed_lookup_machine.rs
similarity index 94%
rename from src/witness_generator/fixed_lookup_machine.rs
rename to src/witness_generator/machines/fixed_lookup_machine.rs
index 733e7aed8..81834f3bd 100644
--- a/src/witness_generator/fixed_lookup_machine.rs
+++ b/src/witness_generator/machines/fixed_lookup_machine.rs
@@ -1,16 +1,17 @@
 use std::collections::{HashMap, HashSet};
 
+use super::Machine;
 use crate::analyzer::{Expression, Identity, IdentityKind, SelectedExpressions};
 use crate::number::{AbstractNumberType, DegreeType};
-use crate::witness_generator::eval_error;
-use crate::witness_generator::expression_evaluator::ExpressionEvaluator;
-use crate::witness_generator::util::contains_witness_ref;
 
-use super::affine_expression::AffineExpression;
-use super::eval_error::EvalError;
-use super::fixed_evaluator::FixedEvaluator;
-use super::machine::Machine;
-use super::{EvalResult, FixedData};
+use crate::witness_generator::{
+    affine_expression::AffineExpression,
+    eval_error::{self, EvalError},
+    expression_evaluator::ExpressionEvaluator,
+    fixed_evaluator::FixedEvaluator,
+    util::contains_witness_ref,
+    EvalResult, FixedData,
+};
 
 /// Machine to perform a lookup in fixed columns only.
 /// It only supports lookup in the first column of the query and will use the first match.
diff --git a/src/witness_generator/machine_extractor.rs b/src/witness_generator/machines/machine_extractor.rs
similarity index 98%
rename from src/witness_generator/machine_extractor.rs
rename to src/witness_generator/machines/machine_extractor.rs
index 3c8d185ea..dc61bfc1d 100644
--- a/src/witness_generator/machine_extractor.rs
+++ b/src/witness_generator/machines/machine_extractor.rs
@@ -4,10 +4,10 @@ use crate::analyzer::{Expression, Identity, SelectedExpressions};
 
 use super::double_sorted_witness_machine::DoubleSortedWitnesses;
 use super::fixed_lookup_machine::FixedLookup;
-use super::machine::Machine;
-
 use super::sorted_witness_machine::SortedWitnesses;
-use super::{FixedData, WitnessColumn};
+use super::FixedData;
+use super::Machine;
+use crate::witness_generator::WitnessColumn;
 
 /// Finds machines in the witness columns and identities
 /// and returns a list of machines and the identities
diff --git a/src/witness_generator/machine.rs b/src/witness_generator/machines/mod.rs
similarity index 92%
rename from src/witness_generator/machine.rs
rename to src/witness_generator/machines/mod.rs
index ea75941d8..6bc14c330 100644
--- a/src/witness_generator/machine.rs
+++ b/src/witness_generator/machines/mod.rs
@@ -6,6 +6,11 @@ use crate::number::AbstractNumberType;
 use super::EvalResult;
 use super::{affine_expression::AffineExpression, eval_error::EvalError, FixedData};
 
+mod double_sorted_witness_machine;
+mod fixed_lookup_machine;
+pub mod machine_extractor;
+mod sorted_witness_machine;
+
 /// A machine is a set of witness columns and identities where the columns
 /// are used on the right-hand-side of lookups. It can process plookups.
 pub trait Machine {
diff --git a/src/witness_generator/sorted_witness_machine.rs b/src/witness_generator/machines/sorted_witness_machine.rs
similarity index 96%
rename from src/witness_generator/sorted_witness_machine.rs
rename to src/witness_generator/machines/sorted_witness_machine.rs
index 1415dda7b..be1aabc6d 100644
--- a/src/witness_generator/sorted_witness_machine.rs
+++ b/src/witness_generator/machines/sorted_witness_machine.rs
@@ -2,17 +2,17 @@ use std::collections::{BTreeMap, HashMap, HashSet};
 
 use itertools::{Either, Itertools};
 
+use super::super::affine_expression::AffineExpression;
+use super::Machine;
+use super::{EvalResult, FixedData};
 use crate::analyzer::{Expression, Identity, IdentityKind, SelectedExpressions};
 use crate::number::AbstractNumberType;
-use crate::witness_generator::eval_error;
-
-use super::affine_expression::AffineExpression;
-use super::eval_error::EvalError;
-use super::expression_evaluator::ExpressionEvaluator;
-use super::fixed_evaluator::FixedEvaluator;
-use super::machine::Machine;
-use super::symbolic_evaluator::SymbolicEvaluator;
-use super::{EvalResult, FixedData};
+use crate::witness_generator::{
+    eval_error::{self, EvalError},
+    expression_evaluator::ExpressionEvaluator,
+    fixed_evaluator::FixedEvaluator,
+    symbolic_evaluator::SymbolicEvaluator,
+};
 
 /// A machine that can support a lookup in a set of columns that are sorted
 /// by one specific column and values in that column have to be unique.
diff --git a/src/witness_generator/mod.rs b/src/witness_generator/mod.rs
index 1d14af836..e7dd78602 100644
--- a/src/witness_generator/mod.rs
+++ b/src/witness_generator/mod.rs
@@ -9,15 +9,11 @@ use self::util::WitnessColumnNamer;
 
 mod affine_expression;
 mod bit_constraints;
-mod double_sorted_witness_machine;
 mod eval_error;
 mod expression_evaluator;
 pub mod fixed_evaluator;
-mod fixed_lookup_machine;
 mod generator;
-mod machine;
-mod machine_extractor;
-mod sorted_witness_machine;
+mod machines;
 pub mod symbolic_evaluator;
 mod util;
 
@@ -49,8 +45,11 @@ pub fn generate<'a>(
         witness_ids: witness_cols.iter().map(|w| (w.name, w.id)).collect(),
         verbose,
     };
-    let (machines, identities) =
-        machine_extractor::split_out_machines(&fixed, &analyzed.identities, &witness_cols);
+    let (machines, identities) = machines::machine_extractor::split_out_machines(
+        &fixed,
+        &analyzed.identities,
+        &witness_cols,
+    );
     let (global_bit_constraints, identities) =
         bit_constraints::determine_global_constraints(&fixed, identities);
     let mut generator = generator::Generator::new(