That can be achieved pretty easily with two packages in LaTeX: xcolor and changebar.

\usepackage{xcolor}
\usepackage{changebar}

Using these, we can define the following commands to mark up additions and deletions:

\newcommand{\removed}[1]{\cbstart\removedfragile{#1}\cbend{}}
\newcommand{\removedfragile}[1]{{\color{red}{#1}}{}}
\newcommand{\added}[1]{\cbstart\addedfragile{#1}\cbend{}}
\newcommand{\addedfragile}[1]{{\color{green!50!black}{#1}}{}}
\newcommand{\changed}[2]{\added{#1}\removed{#2}}

At least from my experience, change bars don’t work in “fragile” environments such as float captions, that’s why there are versions of the commands that only color the edit. With this, we could already do

This \changed{new replacement}{text} is replaced.

to produce the above image. However, what if we want to see the final version only, without the change markup? Let’s define a new if

\newif\ifdiff
\difffalse

and then conditionally define our markup functions:

\ifdiff
  % the above definitions of removed* and added*
\else
  \newcommand{\removed}[1]{} % non-markup version
  \newcommand{\removedfragile}[1]{}
  \newcommand{\added}[1]{#1}
  \newcommand{\addedfragile}[1]{#1}
\fi

Now we can select whether we want to display the edits by setting diff to true or false. You and your reviewers will like it.

You can download the full source code of a sample page, the corresponding output with differences shown and without markup.

Eventually, people arrived on campus. Had some very funny evenings with a couple of new grad students, introduced them to the Austrian way of Åviechan. Thanks for your couch, Jonny!

On my last weekend, I went twice to the Hardly Strictly Bluegrass Festival, a free three-day festival in Golden Gate Park in the heart of San Francisco. So many funny, crazy people there! It seems that for some Californians, the 60s never ended. I particularly enjoyed the performance of Buckethead on Saturday, a rather non-bluegrassy mixture of jazz and hard rock—and yes, he really wears a bucket on his head while playing his various guitars.

I sold my bike—will miss you so much, dear blue beach cruiser! And when I left on Monday, something happened that hasn’t happened for a few months: It started raining.

Now all that’s left to say is, it’s been an awesome summer, goodbye, thanks for reading, and hope to see you soon! I’ll be back.

We didn’t stay long there, anyway. L.A. nightlife, here we come! I still don’t know whether the cab driver brought us to the club we actually wanted to go to, but it seemed he knew a lot about party, so we trusted him. The music there was better than I had expected. At one point, they forced people off the stage and did some photo and video shooting. No idea what exactly was going on or whom the fuzz was all about, but it must’ve been some sort of celebrity.

Oh, did I say “nightlife”? In fact, all bars, clubs, etc have to close at 2:00, so there’s no risk of having fun the whole night. Supermarkets and copy shops are still open at that time though.

After a yummy and way too big breakfast on Sunday, we made a short stop in Hollywood and continued driving to San Diego. This might seem surprising, but the Bristol was a little nicer than the Budget Inn.

Is it a sign of getting older when shopping Banana Republic (what a great name!) while others go to Forever 21? I hope not. At least I found a nice shirt there.

We went to Balboa Park and Coronado Island. Had the first few minutes of rain since I don’t know when. Nevertheless, had a great, relaxed time.

On Tuesday, we slowly made our way back to Los Angeles Airport, stopping at a few beaches to enjoy the sun. Eventually we returned the car and flew back. Nice trip.

There are levels of tidiness.

Tidy.
Very Tidy.
Totally Deranged Tidy.

Geeky Tidy.

After sharing these awesome pictures by the Swiss “artist” Ursus Wehrli with the world, Martin N. pointed out that there is still a severe issue with the Badewiese: People are not even sorted by the colors of their swimsuits! Adding to that, trees are placed in total chaos, not to speak of their leaves; clearly, there are tiny waves on the water; and one can almost see blades of grass not being sorted by size. Obviously, this picture needed further tidying up.

© Ursus Wehrli

Python to the rescue! 5 minutes, 10 lines, and half a beer later I had a program that would load the image, re-arrange its pixels, and save it again:

from PIL import Image

old = Image.open("tidy.jpg")
colors = old.getcolors(old.size[0] * old.size[1])
data = []
for count, color in colors:
    data.extend(count * [color])
data.sort()
new = Image.new('RGB', old.size)
new.putdata(data)
new.save("naive_tidy.png")

This yields the following picture:

So how was this “re-arrangement” performed? In a naïve approach, I just sorted the RGB values of the pixels, which is why there are many consecutive lines (of equal reds) with abrupt changes. Ordered, but far from being tidy.

Let’s try another color space and sort by HSV values—a smooth hue should look better, after all. So by adding

import colorsys

and changing one line to

data.sort(key=lambda rgb: colorsys.rgb_to_hsv(*rgb))

we get the following image:

More beautiful, but the red and white noise in the end doesn’t look tidy at all. We want a smooth transition through all given colors. Hilbert curves to the rescue! Found a ready-to-be-used Hilbert walk implementation, added

import hilbert

and changed the sorting once again to

data.sort(key=hilbert.Hilbert_to_int)

to get this image:

Mathematical computer science just made the world a little tidier.

After that, we spent one night in Lassen Volcanic National Park. After a winter with over seven meters of snow at some places, they still have quite a lot of snow in the middle of summer! We hiked up above 3000 meters towards Lassen Peak, and we saw Bumpass Hell, a stinking but beautiful collection of mud pots and volcanic hot pools.

We continued our trip to the nice campground in McArthur-Burney Falls Memorial State Park and finally reached Lava Beds National Monument. Ages ago, huge streams of lava had created tube caves, when their top cooled and crusted while the inner part kept flowing.

Our companions on the road, among others: Johnny Cash (US), Pink Floyd, Muse (UK), Kruder & Dorfmeister (AT). And the Lowrider, of course.

Endless roads through forests. Desert. Lakes. Campfires. Togetherness. Happiness!

Seth is a really nice guy from the east coast, and he never “slowed down” to the Californian way of speaking—or maybe even living? We had great seafood right at the bay, and he introduced me to his collection of bluegrass music. Will eventually be handy when I maybe go to the big bluegrass festival at the end of September. Oh, and Seth’s house is pretty awesome as well!

We continued our trip on Highway 1 along the beautiful Pacific coast of California to finally reach San Luis Obispo, where Sandy, another friend of Rick, awaited us. Had a great time there, going to Santa Barbara, to the beach, and to the world-famous weekly San Luis Obispo Farmers Market. That tri-tip there was definitely worth the 30-minute queue!

And if you ever happen to be in San Luis Obispo, check out Novo—their tapas are simply great. If you don’t appreciate very spicy food though (Johanna rather doesn’t), just don’t try the chili peppers that come along, they are red and hot! (By the way, did I already mention I recently got tickets for this concert?)

I’ll probably not soon forget being locked in the bathroom for about an hour until the locksmith came to release me.

After very nice days with very nice people we returned back to Palo Alto to rent a car, pick up Rick and Heli from the airport, and continue our trip northwards. But more on that later.

If you want to know the details, here is our exact route.

When we came there at around noon, it didn’t seem like there would be 60,000 people all over the place pretty soon; only a few people in front of the stage and almost no one elsewhere. We had delicious mac & cheese and burritos—typical Californian food—and Heineken—typical Dutch Piss. By the way, the smell in the air all around the festival area also reminded me of Amsterdam.

The music started with a horrible performance of some hip hoppers that didn’t know how to sing or even speak, but continued with cool, funky jazz by The Greyboy Allstars. Then OK Go (see one of their unique videos below), Arcade Fire, and The Black Keys (a pretty cool Ohioan band I hadn’t known before) rocked the stage.

Right on (very American) time at 8:15 the best live band in the world started playing: Muse!

Heavy rock fading into symphonic compositions with classical piano sounds supported by stunning visuals, artificial fog, and lasers—this show had everything. Not only did they play great songs (of which they have plenty, much more than would fit into a single set), their show felt like a well-planned whole, which I appreciate a lot.

Unsurprisingly, they played many songs from their new album “The Resistance”, but they did include sufficiently enough older works as well, even not-so-mainstream-popular ones. And how cool is it to play a few chords of the “House of the Rising Sun” between “Time Is Running Out” and “Starlight”?

Here is Muse propagating the “United States of Eurasia” with very nice visuals in the background:

And here they perform their probably most popular song “Starlight”:

You can also see the complete setlist.

Apart from the music, I was amazed by the fact that there wasn’t even the slightest traffic jam after the festival and all the people went home (mostly by car).