diff --git a/src/calcprime.cpp b/src/calcprime.cpp
index e69de29..a608c42 100644
--- a/src/calcprime.cpp
+++ b/src/calcprime.cpp
@@ -0,0 +1,64 @@
+#include "calcprime.h"
+
+CalcPrime::CalcPrime(QObject *parent)
+    : QObject( parent )
+    , m_bCalculate( false )
+    , m_curValue( 0 )
+    , m_timer()
+    , oForm()
+{
+    m_timer.setInterval( 1 );
+    m_timer.setSingleShot( true );
+
+    connect( &m_timer, &QTimer::timeout, this, &CalcPrime::slotTimeOut );
+
+    connect( &oForm, &CalcPrimeForm::signalStartButtonClicked, this, &CalcPrime::slotStartCalculation );
+    connect( &oForm, &CalcPrimeForm::signalStopButtonClicked, this, &CalcPrime::slotStopCalculation );
+
+    connect( this, &CalcPrime::signalCurrentValue, &oForm, &CalcPrimeForm::slotUpdateCurrentValue );
+    connect( this, &CalcPrime::signalPrimeNumberFound, &oForm, &CalcPrimeForm::slotAddNewPrime );
+
+    oForm.show();
+}
+
+void CalcPrime::slotStartCalculation()
+{
+    m_bCalculate = true;
+    slotTimeOut();
+}
+
+void CalcPrime::slotStopCalculation()
+{
+    m_bCalculate = false;
+}
+
+void CalcPrime::slotTimeOut()
+{
+    emit signalCurrentValue( m_curValue );
+    if( number_is_prime( m_curValue ) )
+    {
+        emit signalPrimeNumberFound( m_curValue );
+    }
+
+    m_curValue++;
+
+    if( m_bCalculate )
+    {
+        m_timer.start();
+    }
+}
+
+bool CalcPrime::number_is_prime(uint64_t number)
+{
+    uint64_t m = number / 2;
+
+    for( uint64_t i = 2; i <= m; i++ )
+    {
+        if( number % i == 0 )
+        {
+            return false;
+        }
+    }
+
+    return true;
+}
diff --git a/src/calcprime.h b/src/calcprime.h
index ce3f30c..157bfac 100644
--- a/src/calcprime.h
+++ b/src/calcprime.h
@@ -1,7 +1,9 @@
 #pragma once
 
 #include "calcprime_form.h"
+
 #include <QObject>
+#include <QTimer>
 
 class CalcPrime : public QObject
 {
@@ -10,10 +12,6 @@ class CalcPrime : public QObject
 public:
     explicit    CalcPrime(QObject *parent = nullptr);
 
-private:
-    bool        m_bCalculate;
-    uint64_t    m_curValue;
-
 signals:
     void        signalCurrentValue( uint64_t current_value );
     void        signalPrimeNumberFound( uint64_t prime_number );
@@ -21,4 +19,16 @@ signals:
 private slots:
     void        slotStartCalculation();
     void        slotStopCalculation();
+    void        slotTimeOut();
+
+private:
+    bool        number_is_prime(uint64_t number);
+
+private:
+    bool        m_bCalculate;
+    uint64_t    m_curValue;
+    QTimer      m_timer;
+
+    CalcPrimeForm   oForm;
+
 };
diff --git a/src/calcprime_form.cpp b/src/calcprime_form.cpp
index d22e9bb..0d23f58 100644
--- a/src/calcprime_form.cpp
+++ b/src/calcprime_form.cpp
@@ -23,7 +23,8 @@ void CalcPrimeForm::slotUpdateCurrentValue( uint64_t value )
 
 void CalcPrimeForm::slotAddNewPrime( uint64_t new_prime )
 {
-    this->listPrimes->addItem(QString( std::to_string( new_prime ).c_str() ));
+    this->listPrimes->insertPlainText(QString( std::to_string( new_prime ).c_str() ) + "\t");
+    this->listPrimes->centerCursor();
 }
 
 void CalcPrimeForm::slotStartButtonClicked()
diff --git a/src/calcprime_form.ui b/src/calcprime_form.ui
index ef2e00e..4e3dd54 100644
--- a/src/calcprime_form.ui
+++ b/src/calcprime_form.ui
@@ -18,13 +18,33 @@
     <layout class="QVBoxLayout" name="verticalLayout">
      <item>
       <widget class="QLCDNumber" name="currentValue">
+       <property name="font">
+        <font>
+         <pointsize>13</pointsize>
+         <bold>true</bold>
+        </font>
+       </property>
+       <property name="styleSheet">
+        <string notr="true">color: rgb(170, 255, 0);
+background-color: rgb(0, 0, 127);</string>
+       </property>
        <property name="digitCount">
         <number>30</number>
        </property>
       </widget>
      </item>
      <item>
-      <widget class="QListWidget" name="listPrimes"/>
+      <widget class="QPlainTextEdit" name="listPrimes">
+       <property name="undoRedoEnabled">
+        <bool>false</bool>
+       </property>
+       <property name="textInteractionFlags">
+        <set>Qt::NoTextInteraction</set>
+       </property>
+       <property name="centerOnScroll">
+        <bool>false</bool>
+       </property>
+      </widget>
      </item>
      <item>
       <layout class="QHBoxLayout" name="horizontalLayout">
@@ -36,6 +56,26 @@
         </widget>
        </item>
        <item>
+        <spacer name="horizontalSpacer_2">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+       <item>
+        <widget class="QPushButton" name="cmdResetButton">
+         <property name="text">
+          <string>Reset</string>
+         </property>
+        </widget>
+       </item>
+       <item>
         <spacer name="horizontalSpacer">
          <property name="orientation">
           <enum>Qt::Horizontal</enum>
diff --git a/src/main.cpp b/src/main.cpp
index f179134..eca95bb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,13 +1,12 @@
 #include <QApplication>
 
-#include "calcprime_form.h"
+#include "calcprime.h"
 
 int main( int argc, char* argv[] )
 {
     QApplication oApp( argc, argv );
 
-    CalcPrimeForm oForm;
-    oForm.show();
+    CalcPrime   ocalcPrime;
 
      oApp.exec();
 }