Due to mandatory scheduled maintenance, the next test is currently unavailable. It has been replaced with a live-fire course designed for military androids. The Enrichment Center apologizes and wishes you the best of luck.

Momentum, a function of mass and velocity, is conserved between portals. In layman's terms, speedy thing goes in, speedy thing comes out.

Remember, the Aperture Science Bring Your Daughter to Work Day is the perfect time to have her tested.

This was a triumph! I'm making a note here: Huge Success. It's hard to overstate my satisfaction. Aperture Science - we do what we must because we can. For the good of all of us, except the ones who are dead. But there's no sense crying over every mistake. You just keep on trying till you run out of cake. And the science gets done. And you make a neat gun. For the people who are still alive. I'm not even angry. I'm being most sincere right now. Even though you broke my heart and killed me. And tore me to pieces. And threw every piece into a fire. As they burned, it hurt because I was so happy for you. Now these points of data make a beautiful line. And we're out of beta; we're releasing on time. So I'm GLaD I got burned. Think of all the things we learned. For the people who are still alive. Go ahead and leave me. I think I prefer to stay inside. Maybe you'll find someone else to help you. Maybe Black Mesa. That was a joke - Ha Ha! Fat Chance! Anyway, this cake is great. It's so delicious and moist. Look at me still talking when there's science to do. When I look out there, it makes me GLaD I'm not you. I've experiments to run. There is research to be done. On the people who are still alive. And, believe me, I'm still alive! I'm doing science and I'm still alive! I feel FANTASTIC and I'm still alive! While you're dying, I'll be still alive! And when you're dead, I will be still alive! Still Alive! Still Alive...

While it has been a faithful companion, your Companion Cube cannot accompany you through the rest of the test. If it could talk - and the Enrichment Center takes this opportunity to remind you that it cannot - it would tell you to go on without it, because it would rather die in a fire than become a burden to you.