diff --git a/src/lib/Pipeline.class.ts b/src/lib/Pipeline.class.ts
index 2986e4e..0907ff6 100644
--- a/src/lib/Pipeline.class.ts
+++ b/src/lib/Pipeline.class.ts
@@ -5,19 +5,21 @@ import chalk from "chalk";
 import Stage from "./Stage.class.js";
 import duration from "../utils/duration.js";
 import path from "node:path";
-import { mkdirSync } from "node:fs";
+import * as fs from "node:fs";
 
 class Pipeline {
   public readonly stages = new Map<string, Stage>();
   public dataDir: string;
   private $isValidated: boolean = false;
+  private stageNames: string[] = [];
+  private now = new Date();
 
   public constructor(
     private readonly $configuration: LDWorkbenchConfiguration
   ) {
     //  create data folder:
     this.dataDir = path.join("data", kebabcase(this.$configuration.name));
-    mkdirSync(this.dataDir, { recursive: true });
+    fs.mkdirSync(this.dataDir, { recursive: true });
   }
 
   private error(e: Error, stage?: string): void {
@@ -45,6 +47,11 @@ class Pipeline {
   public validate(): void {
     if (this.$isValidated) return;
     let i = 0;
+    if (this.$configuration.stages.length === 0) {
+      throw new Error(
+        "Your pipeline contains no stages."
+      );
+    }
     for (const stageConfiguration of this.$configuration.stages) {
       if (i === 0 && stageConfiguration.iterator.endpoint === undefined) {
         throw new Error(
@@ -70,28 +77,38 @@ class Pipeline {
   }
 
   public async run(startFromStageName?: string): Promise<void> {
-    const now = new Date();
+    this.now = new Date();
     console.info(chalk.cyan(`🏁 starting pipeline "${chalk.bold(this.name)}"`));
     const spinner = ora("validating pipeline").start();
-    let startFromStage = 0
+    let startFromStage = 0;
     try {
       this.validate();
       if (startFromStageName !== undefined) {
-        if(/^\d+$/.test(startFromStageName)) {
-          const ix = parseInt(startFromStageName)
+        if (/^\d+$/.test(startFromStageName)) {
+          const ix = parseInt(startFromStageName);
           if (Array.from(this.stages.keys()).length < ix) {
-            const e = new Error(`Pipeline ${chalk.italic(this.name)} does not have stage #${chalk.italic(startFromStageName)}.`)
+            const e = new Error(
+              `Pipeline ${chalk.italic(
+                this.name
+              )} does not have stage #${chalk.italic(startFromStageName)}.`
+            );
             spinner.fail(e.message);
             this.error(e);
           } else {
-            startFromStage = ix - 1
+            startFromStage = ix - 1;
           }
-        } else if(!this.stages.has(startFromStageName)) {
-          const e = new Error(`Pipeline ${chalk.italic(this.name)} does not have stage ${chalk.italic(startFromStageName)}.`)
+        } else if (!this.stages.has(startFromStageName)) {
+          const e = new Error(
+            `Pipeline ${chalk.italic(
+              this.name
+            )} does not have stage ${chalk.italic(startFromStageName)}.`
+          );
           spinner.fail(e.message);
           this.error(e);
         } else {
-          startFromStage = Array.from(this.stages.keys()).findIndex(value => value === startFromStageName)
+          startFromStage = Array.from(this.stages.keys()).findIndex(
+            (value) => value === startFromStageName
+          );
         }
       }
       spinner.succeed();
@@ -100,32 +117,62 @@ class Pipeline {
       this.error(e as Error);
     }
 
-    const stageNames = Array.from(this.stages.keys()).splice(startFromStage)
+    this.stageNames = Array.from(this.stages.keys()).splice(startFromStage);
 
-    function run(stages: Map<string, Stage>): void {
-      const stage = stages.get(stageNames.shift()!)!
-      const spinner = ora("Loading results from Iterator").start();
-      stage.on("iteratorResult", ($this) => {
-        spinner.text = $this.value;
-      });
-      stage.on("end", (iris, statements) => {
-        spinner.succeed(`stage "${chalk.bold(stage.name)}" resulted in ${statements} statement${statements === 1 ?'':'s'} in ${iris} iteration${iris === 1 ?'':'s'}.`)
-        if (stageNames.length !== 0) {
-          run(stages)
-        } else {
+    Array.from(this.stages.keys()).slice(0, startFromStage).forEach(stagename => {
+      ora().start().info(`stage "${chalk.bold(stagename)}" was skipped`).stop();
+    })
+    this.runRecursive();
+  }
+
+  private runRecursive(): void {
+    const stage = this.stages.get(this.stageNames.shift()!)!;
+    const spinner = ora("Loading results from Iterator").start();
+    stage.on("iteratorResult", ($this) => {
+      spinner.text = $this.value;
+    });
+    stage.on("end", (iris, statements) => {
+      spinner.succeed(
+        `stage "${chalk.bold(
+          stage.name
+        )}" resulted in ${statements.toLocaleString()} statement${
+          statements === 1 ? "" : "s"
+        } in ${iris.toLocaleString()} iteration${iris === 1 ? "" : "s"}.`
+      );
+      if (this.stageNames.length !== 0) {
+        this.runRecursive();
+      } else {
+        this.concat()
           console.info(
-            chalk.green(`✔ your pipeline was completed in ${duration(now)}`)
+            chalk.green(
+              `✔ your pipeline "${chalk.bold(
+                this.name
+              )}" was completed in ${duration(this.now)}}`
+            )
           );
-        }
-      });
-      try {
-        stage.run()
-      } catch(e) {
-        spinner.fail((e as Error).message);
       }
+    });
+    try {
+      stage.run();
+    } catch (e) {
+      spinner.fail((e as Error).message);
     }
+  }
 
-    run(this.stages)
+  private concat(): void {
+    const spinner = ora("Combining statements from all stages:").start();
+    const destinationPath = path.join(this.dataDir, 'statements.nt')
+    const destinationStream = fs.createWriteStream(destinationPath, {flags:'a'})
+    const stageNames = Array.from(this.stages.keys())
+    for (const stageName of stageNames) {
+      spinner.suffixText = chalk.bold(stageName)
+      fs.readFile(this.stages.get(stageName)!.destinationPath, (error, buffer) => {
+        if(error !== null) throw error
+        destinationStream.write(buffer)
+      })
+    }
+    spinner.suffixText = chalk.bold(destinationPath)
+    spinner.succeed()
   }
 
   get name(): string {