diff --git a/moose/materials.py b/moose/materials.py
index 0c67f55..71ca266 100644
--- a/moose/materials.py
+++ b/moose/materials.py
@@ -156,9 +156,9 @@ def __str__(self):
         string =  f'[{self.name}]\n'
         string += f'type={self.material_type.name}\n'
         prop_names = ' '.join(self.prop_names)
-        string += f'prop_names={prop_names}\n'
+        string += f'prop_names=\'{prop_names}\'\n'
         prop_values = ' '.join([x.name for x in self.prop_values])
-        string += f'prop_values={prop_values}\n'
+        string += f'prop_values=\'{prop_values}\'\n'
         if self.block:
             string += f'block="{self.block}"\n'
         string += '[]\n'
diff --git a/moose/moose.py b/moose/moose.py
index f9067e1..7acbaf4 100644
--- a/moose/moose.py
+++ b/moose/moose.py
@@ -45,6 +45,7 @@ def write(self, filename):
         file = open(filename,'w')
         # first the mesh block
         if self.mesh: file.write(indent(self.mesh.__str__()))
+        if self.problem: file.write(indent(self.problem.__str__()))
         if self.global_params: file.write(indent(self.global_params.__str__()))
         if self.variables: file.write(indent(self.variables.__str__()))
         if self.aux_variables: file.write(indent(self.aux_variables.__str__()))
diff --git a/moose/variables.py b/moose/variables.py
index bd7ccfc..68090a8 100644
--- a/moose/variables.py
+++ b/moose/variables.py
@@ -28,32 +28,37 @@ class Family(IntEnum):
     SIDE_HIERARCHIC = auto()
     
 class Variable():
-    def __init__(self, name = "", order = 1, family = 1, block = ""):
+    def __init__(self, name="", order=None, family=None, block="", initial_condition=""):
         self.name = name
-        self.order = Order(order)
-        self.family = Family(family)
+        self.order = Order(order) if order is not None else None
+        self.family = Family(family) if family is not None else None
         self.block = block
+        self.initial_condition = initial_condition
 
     def __str__(self):
         string = f'[{self.name}]\n'
-        string += f'order = {self.order.name}\n'
-        string += f'family = {self.family.name}\n'
+        if self.order:
+            string += f'order = {self.order.name}\n'
+        if self.family:
+            string += f'family = {self.family.name}\n'
+        if self.initial_condition:
+            string += f'initial_condition = "{self.initial_condition}"\n'
         if self.block:
             string += f'block = "{self.block}"\n'
-        string += f'[]\n'
+        string += '[]\n'
         return string
-
+        
 class AuxVariable(Variable):
-    def __init__(self, name = "", order = 1, family = 1, block = ""):
-        super().__init__(name,order,family,block)
+    def __init__(self, name="", order=None, family=None, block="", initial_condition=""):
+        super().__init__(name, order, family, block, initial_condition)
 
 class Variables():
     def __init__(self):
         self.name = "Variables"
         self.variables = {}
 
-    def add_variable(self, name, order, family, block):
-        variable = Variable(name=name,order=order,family=family,block=block)
+    def add_variable(self, name, order=None, family=None, block="", initial_condition=""):
+        variable = Variable(name=name, order=order, family=family, block=block, initial_condition=initial_condition)
         if variable.name in self.variables.keys():
             print("variable name already in use")