More than twenty years ago - my life had little to do with visual arts - my friend T. took me to the entrance hall of the Stadhuis metro station. T. was not a graffiti artist with a short criminal record, but he had renounced his childhood sins and was now working as a graphic designer. We descended the stairs on the side of Stadhuisplein and he pointed me to the wall between the stairs, where a number of white polished concrete panels had been attached. "Look, this is it," he said. Like every Rotterdammer, I had already passed the wall many times, but never before had I bothered to look closely at the artwork, because that was it. The four panels were painted, or rather drawn in, or perhaps even better, scratched with black lines, sketches, curves, patterns and surfaces, which at first sight seemed to be a drawing in the making, but on closer inspection perhaps the disintegration and disintegration of a drawing seemed to depict. Even at first glance, the performance seemed to be evidence of a high degree of abstraction, but if you looked long enough, recognizability would increase. Now I also saw human and robot figures, plans of a metro network, stair galleries, cranes and levers, even the Hefbrug, but also energy circuits and schematic manuals of electrical devices. Maybe it was a manual for the city, paper architecture - maybe we were looking at the Rotterdam of reconstruction, but then as a series of thoughts and lines that precede the construction of a city, such as in the 17de century mathematics was seen as the exposed thoughts of God before creation. The drawings seemed to fan out over the panels, as if an unknown force of nature had exerted violence at the center of the composition.

T. sat down on his knees in front of work and ran his fingers across the black lines. "You have to feel it," he said. He closed his eyes and, as if it were Braille, he read the drawing with his hands. "I have felt it so many times," he continued, "that I can copy entire fragments at home." To reinforce his remark, he opened his eternal sketchbook, and showed me the pages on which a black stylus had written scratches, lines and surfaces in the white paper. Although his scribbles were noticeably tighter, I did see the kinship. According to T., the metro artwork was a fabulous incentive to drawing and an ode to the enjoyment of drawing. "Lesson No.1," he called the work. He had grown up in the company of the Lijnbaan youth; youngsters with a great interest in graffiti and murals. The territory of the youngsters was marked by Lee's Piece in the Bear Pit and by the Chilean Column in front of the central station. "The youth from all over the country gathered here," wrote a colleague of T. in a memory of the Lijnbaan youths. "They looked at the works, discussed them with each other and then set off to create themselves." Some of them, including T., also gave the artwork to the Stadhuis metro station an iconic status. The work became one of the scarce official works of art that, amid hundreds of illegal graffiti, also gained an international reputation as an early example of 'Subway Art'. "Look here, and here, and another one here," said T., pointing out a number of lines and planes. "They were spontaneously signed by others - this work is not finished at all and requires participation."

Thanks to the guest lecture by T. this piece also got a place in my cultural awareness. The work, which is under the title Graphic Wall, was added to the annals of Rotterdam art history, was delivered in 1968 by artist Bouke Ylstra during the opening of the metro station. The wall is one of the few metro works that have stood the test of time with flying colors. The drawing differs not only from the typical and somewhat pompous monumental wall art in the stations on the north side of the Maas - think of the works of Henk de Vos and Ger van Iersel, but also of the then ubiquitous interventions by Carla Kaper, Peter Dumas and Leen Droppert in the stations on the southern Maas bank. Bouke Ylstra was not old-fashioned and not hip - that must be the timeless secret of his wall. Moreover, the Graphic Wall to persuade viewers to become superlatives today, including Rotterdam-based designer Reinier de Jong, who ranks this 'beautiful abstract work in the metro station' among the highlights of public design in Rotterdam on his website. Equally intriguing is a smaller, but somewhat comparable, work that Ylstra made in 1963 on the outer and inner walls of the former municipal printing works in Bredestraat, just behind Mariniersweg. You have to look carefully, but once you've seen it, it's worth a regular bike ride.

An interview with Bouke Ylstra from 1997 opened with a quote that could also have been written from my comrade T.'s mouth: "Drawing is the beginning of everything: drawing, noting, practicing." That insight apparently also applied to those who love his work. Since the completion of the Graphic Wall It rained complaints about the minor additions and corrections that passers-by added to his work. 'Unfortunately, there are always strangers who give in to the tendency to add something to the performance', critic Dolf Welling complained in the mid-1980s. But perhaps this form of intended or unintended interactivity also says something about the nature of the work of Ylstra, about his undisguised love for drawing, for example, shamelessly promoted in public space, or about the iron discipline that the writers in the field of Street Art so appreciate - their almost autistic fixation on drawing, writing down, practicing. Without realizing it, Dolf Welling also discussed the Graphic Wall like a graffiti work that asked for presence and provocation. He regarded the work as a 'spontaneous, nervous writing', spoke of the composition as a 'playfully formed line writing', saw 'not yet exactly named shapes', and called the drawing suggestive, 'evocative', that is to say that the representation evokes images in viewers that stimulate the mind.

It is tempting to categorize Bouke Ylstra today as a monumental artist, as an exponent of reconstruction art. In the nice overview work Art of reconstruction in the Netherlands 1940-1965 (2013), published under the auspices of the Cultural Heritage Agency of the Netherlands, portrays the thirty most striking monumental artists, including Ylstra. "He was first and foremost a graphic artist and painter," the book notes, "but thanks to monumental assignments he was able to make ends meet from his work." His monumental oeuvre has highs and lows. Indeed, Ylstra said in 1997. "Money is an important factor. I have done hundreds of assignments. But when I look back on those works, I see that I have not always escaped temptation. Well, you have a family, a house and a studio with fixed costs that are difficult to pay in liberal art. And I did not want to make use of the Visual Artists Regulation '.

Just like T. I see Bouke Ylstra as a draftsman for everything. His graphic works in the Stadhuisplein metro station and in the Bredestraat remained very close to the free work he made during that period. "I draw a lot," he said in an interview. 'I always have a sketchbook with me, even when I'm in a restaurant, because I am bored with the food. Drawing is the mother of all arts - the beginning of all garbage.

Bouke Ylstra probably lived in Dordrecht, but was a Rotterdam artist par excellence. He enjoyed the way Louis van Roode painted, hung around in the infamous Pardoel artists' café, and was not tempted by theoretical reflections on art, which he summarized in the concept of "Amsterdam new lightery." You talked about art in a Rotterdam way, he said, like: "Hey, you can't do anything about it." Rotterdammers preferred the craft, so drawing, noting and practicing. Ylstra could not tell anything meaningful about his own art; he just drew. "I can't talk about the content," he said, "it's unnamed, it's just coming about, it's a story that doesn't stand still. Drawing is a fantastic profession, in which I am completely happy. But applause is needed, because if you do not do that, it will be rotten '.

A story that doesn't stand still. I also see that dynamic in the Graphic Wall, with and without the illegal additions by black felt-tip pens. Much has been written about the technique of the work, more than about the work itself. Perhaps because we like to confuse art and craft in Rotterdam. Some critics call his wall a sgraffito, others speak of marble niello, intarsia or incrustation - beautiful concepts that now evoke nostalgia for bygone times, suggesting that monumental art has become part of the domain of paleontology. Well, Bouke Ylstra mastered many techniques and was an all-rounder, the newspaper wrote Trouw once, but "with a few simple lines he could evoke an entire world."

We also see this simplicity in the Stadhuis metro station and in the Bredestraat. No other work in the public space of Rotterdam looks like this. They stand on their own and you immediately know who made them: "Look, that's a Ylstra." Both drawings are averse to the views on monumentality that prevailed at the time, are indifferent to the client, do not pay lip service to views on general accessibility, and are not aimed at effect. They are what they are: pages from the open sketchbook by Bouke Ylstra.

Art, our mutual friend Thom Holterman says, must be judged on its 'refractive power'. According to him, the Central Station, with its silver shark beak, deserves a symbol and logo of grabbing neo-liberalism, a work of art that radically breaks with that symbolism. Bouke Ylstra's drawings actually have that capacity. Whoever visits the Stadhuis metro station or Bredestraat, is not immediately affected by an inspiring environment. And then I still express myself in a nuanced way. The art here makes no effort to disguise that desolation. Because the chance is certainly not small that you, like Bouke, will be bored there, his displayed subjection to drawing offers a beneficial escape clause. But also a new insight: in the beginning there was drawing, then the garbage came. I think my friend T. would nod in agreement.