diff --git a/Layer.cpp b/Layer.cpp
index ae60067..da1b4ca 100644
--- a/Layer.cpp
+++ b/Layer.cpp
@@ -24,7 +24,7 @@ void Layer::setOutputValues(const std::vector<double> & outputValues)
 
 void Layer::feedForward(const Layer &inputLayer)
 {	
-	for (int neuronNumber = 0; neuronNumber < sizeWithoutBiasNeuron(); ++neuronNumber)
+    for (size_t neuronNumber = 0; neuronNumber < sizeWithoutBiasNeuron(); ++neuronNumber)
 	{
 		at(neuronNumber).feedForward(inputLayer.getWeightedSum(neuronNumber));
 	}
diff --git a/gui/NeuroUI/NeuroUI.pro b/gui/NeuroUI/NeuroUI.pro
index 2d4de34..5a88fef 100644
--- a/gui/NeuroUI/NeuroUI.pro
+++ b/gui/NeuroUI/NeuroUI.pro
@@ -13,8 +13,19 @@ TEMPLATE = app
 
 
 SOURCES += main.cpp\
-        neuroui.cpp
+        neuroui.cpp \
+    ../../Layer.cpp \
+    ../../Net.cpp \
+    ../../Neuron.cpp \
+    netlearner.cpp
 
-HEADERS  += neuroui.h
+HEADERS  += neuroui.h \
+    ../../Layer.h \
+    ../../Net.h \
+    ../../Neuron.h \
+    netlearner.h
 
 FORMS    += neuroui.ui
+
+RESOURCES += \
+    icons.qrc
diff --git a/gui/NeuroUI/icons.qrc b/gui/NeuroUI/icons.qrc
new file mode 100644
index 0000000..807350d
--- /dev/null
+++ b/gui/NeuroUI/icons.qrc
@@ -0,0 +1,2 @@
+<RCC/>
+
diff --git a/gui/NeuroUI/netlearner.cpp b/gui/NeuroUI/netlearner.cpp
new file mode 100644
index 0000000..1dd73c8
--- /dev/null
+++ b/gui/NeuroUI/netlearner.cpp
@@ -0,0 +1,65 @@
+#include "netlearner.h"
+#include "../../Net.h"
+
+void NetLearner::run()
+{
+    try
+    {
+        Net myNet({2, 3, 1});
+
+        size_t batchSize = 5000;
+        size_t batchIndex = 0;
+        double batchMaxError = 0.0;
+        double batchMeanError = 0.0;
+
+        size_t numIterations = 1000000;
+        for (size_t iteration = 0; iteration < numIterations; ++iteration)
+        {
+            std::vector<double> inputValues =
+            {
+                std::rand() / (double)RAND_MAX,
+                std::rand() / (double)RAND_MAX
+            };
+
+            std::vector<double> targetValues =
+            {
+                (inputValues[0] + inputValues[1]) / 2.0
+            };
+
+            myNet.feedForward(inputValues);
+
+            std::vector<double> outputValues = myNet.getOutput();
+
+            double error = outputValues[0] - targetValues[0];
+
+            batchMeanError += error;
+            batchMaxError = std::max<double>(batchMaxError, error);
+
+            if (batchIndex++ == batchSize)
+            {
+                QString logString;
+
+                logString.append("Batch error (");
+                logString.append(QString::number(batchSize));
+                logString.append(" iterations, max/mean): ");
+                logString.append(QString::number(std::abs(batchMaxError)));
+                logString.append(" / ");
+                logString.append(QString::number(std::abs(batchMeanError / batchSize)));
+
+                emit logMessage(logString);
+
+                batchIndex = 0;
+                batchMaxError = 0.0;
+                batchMeanError = 0.0;
+            }
+
+            myNet.backProp(targetValues);
+        }
+    }
+    catch (std::exception &ex)
+    {
+        QString logString("Error: ");
+        logString.append(ex.what());
+        emit logMessage(logString);
+    }
+}
diff --git a/gui/NeuroUI/netlearner.h b/gui/NeuroUI/netlearner.h
new file mode 100644
index 0000000..78e0131
--- /dev/null
+++ b/gui/NeuroUI/netlearner.h
@@ -0,0 +1,17 @@
+#ifndef NETLEARNER_H
+#define NETLEARNER_H
+
+#include <QThread>
+
+class NetLearner : public QThread
+{
+    Q_OBJECT
+
+private:
+    void run() Q_DECL_OVERRIDE;
+
+signals:
+    void logMessage(const QString &logMessage);
+};
+
+#endif // NETLEARNER_H
diff --git a/gui/NeuroUI/neuroui.cpp b/gui/NeuroUI/neuroui.cpp
index b2ebfab..800baf9 100644
--- a/gui/NeuroUI/neuroui.cpp
+++ b/gui/NeuroUI/neuroui.cpp
@@ -12,3 +12,36 @@ NeuroUI::~NeuroUI()
 {
     delete ui;
 }
+
+void NeuroUI::on_runButton_clicked()
+{
+    ui->logView->clear();
+
+    if (m_netLearner == nullptr)
+    {
+        m_netLearner.reset(new NetLearner);
+    }
+
+    connect(m_netLearner.get(), &NetLearner::logMessage, this, &NeuroUI::logMessage);
+
+    connect(m_netLearner.get(), &NetLearner::started, this, &NeuroUI::netLearnerStarted);
+    connect(m_netLearner.get(), &NetLearner::finished, this, &NeuroUI::netLearnerFinished);
+
+    m_netLearner->start();
+}
+
+void NeuroUI::logMessage(const QString &logMessage)
+{
+    ui->logView->addItem(logMessage);
+    ui->logView->scrollToBottom();
+}
+
+void NeuroUI::netLearnerStarted()
+{
+    ui->runButton->setEnabled(false);
+}
+
+void NeuroUI::netLearnerFinished()
+{
+    ui->runButton->setEnabled(true);
+}
diff --git a/gui/NeuroUI/neuroui.h b/gui/NeuroUI/neuroui.h
index 65d4cd8..af2481f 100644
--- a/gui/NeuroUI/neuroui.h
+++ b/gui/NeuroUI/neuroui.h
@@ -3,18 +3,31 @@
 
 #include <QMainWindow>
 
+#include <memory>
+
+#include "netlearner.h"
+
 namespace Ui {
-class NeuroUI;
+    class NeuroUI;
 }
 
 class NeuroUI : public QMainWindow
 {
     Q_OBJECT
 
+private:
+    std::unique_ptr<NetLearner> m_netLearner;
+
 public:
     explicit NeuroUI(QWidget *parent = 0);
     ~NeuroUI();
 
+private slots:
+    void on_runButton_clicked();
+    void logMessage(const QString &logMessage);
+    void netLearnerStarted();
+    void netLearnerFinished();
+
 private:
     Ui::NeuroUI *ui;
 };
diff --git a/gui/NeuroUI/neuroui.ui b/gui/NeuroUI/neuroui.ui
index 4f32e25..325da06 100644
--- a/gui/NeuroUI/neuroui.ui
+++ b/gui/NeuroUI/neuroui.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>400</width>
-    <height>300</height>
+    <width>597</width>
+    <height>389</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -16,22 +16,19 @@
   <widget class="QWidget" name="centralWidget">
    <layout class="QVBoxLayout" name="verticalLayout_2">
     <item>
-     <widget class="QListView" name="logView"/>
+     <widget class="QListWidget" name="logView"/>
     </item>
     <item>
      <layout class="QHBoxLayout" name="horizontalLayout">
       <item>
-       <spacer name="horizontalSpacer">
-        <property name="orientation">
-         <enum>Qt::Horizontal</enum>
+       <widget class="QProgressBar" name="progressBar">
+        <property name="value">
+         <number>0</number>
         </property>
-        <property name="sizeHint" stdset="0">
-         <size>
-          <width>40</width>
-          <height>20</height>
-         </size>
+        <property name="textVisible">
+         <bool>false</bool>
         </property>
-       </spacer>
+       </widget>
       </item>
       <item>
        <widget class="QPushButton" name="runButton">