Initialized all classes.

Completed Tile.cs
Completed TilePattern.cs
Completed CalcPiecesPerHour method in Company.cs

Mosaic/Company.cs

@@ -22,7 +22,11 @@ public sealed class Company
     public Company(string name, decimal m2Price, decimal hourlyWage, 
         int profitMarginPercent, Worker[] workers)
     {
-        // TODO
+        Name = name;
+        _m2Price = m2Price;
+        _hourlyWage = hourlyWage;
+        _profitMargin = profitMarginPercent;
+        _workers = workers;
     }
 
     /// <summary>
@@ -39,6 +43,7 @@ public sealed class Company
     public decimal GetCostEstimate(TilePattern pattern)
     {
         // TODO
+        return 0;
     }
 
     /// <summary>
@@ -50,6 +55,30 @@ public sealed class Company
     /// <returns>Number of tiles this company is able to place per hour</returns>
     private double CalcPiecesPerHour(PatternStyle patternStyle)
     {
-        // TODO
+        double piecesPerHour = 0;
+        for (int i = 0; i < _workers.Length; i++)
+        {
+            double pieces = DefaultPiecesPerHour;
+            
+            // pieces based on worker's speed
+            if (_workers[i].WorkSpeed == WorkSpeed.Fast)
+            {
+                pieces += 5;
+            }
+            else if (_workers[i].WorkSpeed == WorkSpeed.Slow)
+            {
+                pieces -= 5;
+            }
+            
+            // pieces based on pattern complexity
+            if (patternStyle == PatternStyle.Complex)
+            {
+                pieces /= 2;
+            }
+            
+            piecesPerHour += pieces;
+        }
+
+        return piecesPerHour;
     }
 }

Mosaic/Tile.cs

@@ -5,5 +5,62 @@
 /// </summary>
 public sealed class Tile
 {
-    // TODO
+    private readonly TileStyle _style;
+    private readonly int _width;
+    private readonly int _height;
+    public readonly int Area;
+
+    public Tile(TileStyle style, int width, int height)
+    {
+        _style = style;
+        _width = width;
+        _height = height;
+        Area = width * height;
+    }
+
+    public decimal CalcProductionCost()
+    {
+        decimal pricePerCm = 0.016M;
+
+        decimal sizeFactor = 1;
+        switch (Area)
+        {
+            case < 100:
+                sizeFactor = 1.5M;
+                break;
+            case < 400:
+                sizeFactor = 1.2M;
+                break;
+            case > 2500:
+                if (Area > 8100)
+                {
+                    sizeFactor = 1.8M;
+                    break;
+                }
+                sizeFactor = 1.6M;
+                break;
+        }
+        
+        decimal styleFactor = 1;
+        switch (_style)
+        {
+            case TileStyle.Raw:
+                styleFactor = 0.8M;
+                break;
+            case TileStyle.FancyColor:
+                styleFactor = 1.1M;
+                break;
+            case TileStyle.SimplePattern:
+                styleFactor = 1.25M;
+                break;
+            case TileStyle.Ornate:
+                styleFactor= 2.3M;
+                break;
+        }
+        
+        decimal areaInCm = Area / 100M;
+        decimal cost = areaInCm * pricePerCm * sizeFactor * styleFactor;
+        
+        return cost;
+    }
 }

Mosaic/TilePattern.cs

@@ -5,5 +5,39 @@
 /// </summary>
 public class TilePattern
 {
-    // TODO
+    private readonly Tile[] _tiles;
+    public readonly PatternStyle Style;
+
+    public double Area
+    {
+        get
+        {
+            double area = 0;
+            foreach (var tile in _tiles)
+            {
+                area += tile.Area;
+            }
+
+            return area / 1000000;
+        }
+    }
+
+    public int Pieces => _tiles.Length;
+
+    public TilePattern(PatternStyle style, Tile[] tiles)
+    {
+        Style = style;
+        _tiles = tiles;
+    }
+    
+    public decimal CalcProductionCost()
+    {
+        decimal productionCost = 0;
+        foreach (var tile in _tiles)
+        {
+            productionCost += tile.CalcProductionCost();
+        }
+
+        return productionCost;
+    }
 }