diff --git a/src/pystencils/functions.py b/src/pystencils/sympyextensions/pointers.py
similarity index 95%
rename from src/pystencils/functions.py
rename to src/pystencils/sympyextensions/pointers.py
index 76fbb70742352cf9d5627fe012652bb064acdfed..130338c99583bc4874b53cc804f4ff4761f0e580 100644
--- a/src/pystencils/functions.py
+++ b/src/pystencils/sympyextensions/pointers.py
@@ -1,5 +1,5 @@
 import sympy as sp
-from .types import PsPointerType
+from ..types import PsPointerType
 
 
 class AddressOf(sp.Function):
diff --git a/src/pystencils/rng.py b/src/pystencils/sympyextensions/rng.py
similarity index 99%
rename from src/pystencils/rng.py
rename to src/pystencils/sympyextensions/rng.py
index 221505a109beee4a66cd26d525b986ed8b324899..5f1006f0f3b0ce8ca7e72100a72f008cc92c0dac 100644
--- a/src/pystencils/rng.py
+++ b/src/pystencils/sympyextensions/rng.py
@@ -7,6 +7,7 @@ from pystencils.sympyextensions import TypedSymbol, CastFunc
 # from pystencils.backends.cbackend import CustomCodeNode # TODO nbackend: replace
 from pystencils.sympyextensions import fast_subs
 
+
 # class RNGBase(CustomCodeNode): TODO nbackend: replace
 class RNGBase:
 
diff --git a/src/pystencils/sympyextensions/typed_sympy.py b/src/pystencils/sympyextensions/typed_sympy.py
index 7e9edaab123cf9dbb837a6588c4084fe58bda9de..949aa699180c5d770128292ab7766d22cac61a71 100644
--- a/src/pystencils/sympyextensions/typed_sympy.py
+++ b/src/pystencils/sympyextensions/typed_sympy.py
@@ -142,8 +142,7 @@ class FieldShapeSymbol(TypedSymbol):
     def __new_stage2__(cls, field_name: str, coordinate: int):
         from ..defaults import DEFAULTS
 
-        names = "_".join([field_name for field_name in field_names])
-        name = f"_size_{names}_{coordinate}"
+        name = f"_size_{field_name}_{coordinate}"
         obj = super(FieldShapeSymbol, cls).__xnew__(
             cls, name, DEFAULTS.index_dtype, positive=True
         )
diff --git a/tests/test_address_of.py b/tests/test_address_of.py
index c0a75e540237aa2e0ff46af37859c19cc069ce59..0d25be62c145032ee8e3c298da45543ff835d63d 100644
--- a/tests/test_address_of.py
+++ b/tests/test_address_of.py
@@ -4,7 +4,7 @@ Test of pystencils.data_types.address_of
 import pytest
 import pystencils
 from pystencils.typing import PointerType, CastFunc, BasicType
-from pystencils.functions import AddressOf
+from pystencils.sympyextensions.pointers import AddressOf
 from pystencils.simp.simplifications import sympy_cse
 
 import sympy as sp
diff --git a/tests/test_fvm.py b/tests/test_fvm.py
index 0b103e52554f767a0948509e8cae084c1af9e124..e10874cbdf27abe161510e57242f1232f60a6d53 100644
--- a/tests/test_fvm.py
+++ b/tests/test_fvm.py
@@ -3,7 +3,7 @@ import pystencils as ps
 import numpy as np
 import pytest
 from itertools import product
-from pystencils.rng import random_symbol
+from pystencils.sympyextensions.rng import random_symbol
 from pystencils.sympyextensions.astnodes import SympyAssignment
 from pystencils.node_collection import NodeCollection
 
diff --git a/tests/test_random.py b/tests/test_random.py
index 63cd61494b675acbc1675277ff9eb9b1f57ddb3e..6c3a888db86ff7e3b3ed100961643e3cdf36231b 100644
--- a/tests/test_random.py
+++ b/tests/test_random.py
@@ -5,7 +5,7 @@ import pytest
 import pystencils as ps
 from pystencils.sympyextensions.astnodes import SympyAssignment
 from pystencils.node_collection import NodeCollection
-from pystencils.rng import PhiloxFourFloats, PhiloxTwoDoubles, AESNIFourFloats, AESNITwoDoubles, random_symbol
+from pystencils.sympyextensions.rng import PhiloxFourFloats, PhiloxTwoDoubles, AESNIFourFloats, AESNITwoDoubles, random_symbol
 from pystencils.backends.simd_instruction_sets import get_supported_instruction_sets
 from pystencils.cpu.cpujit import get_compiler_config
 from pystencils.typing import TypedSymbol