#880: Rerooter

Tree roots tend to cause damage to water pipes, sewers and foundations. This is especially true in arid places -like my in-laws
garden in Melbourne.

Many ‘solutions’ involve killing the trees by feeding them eg copper sulphate via a porous pipe.


Today’s invention is a way to decoy roots effectively without killing too much foliage. A vertical, porous pipe is sunk into the lawn, causing it minimal damage. As well as water-passing pores, the pipe contains holes big enough to allow small roots to pass inside without damaging the ceramic of the pipe. A very small reservoir drips water onto the top edge of the pipe, keeping it just moist enough to attract the roots.

A cylindrical steel liner, containing large, sharp-edged holes, is then forced down the inside of the pipe, chopping off the most recent small roots which have penetrated and collecting these in its base. The liner can be withdrawn and the choppings buried elsewhere in the garden, away from buildings, etc -thus reclaiming the water they contain.

#879: Tagography

Looking at the details of my del.icio.us account, I realised that I could see the notes which other people had stored about the same article as I had just tagged.

I’ve always had a penchant for precis; never really understanding the need for many words when a few, well chosen ones suffice. Today’s invention is a program which looks through the selections of text people have saved in connection with a given article. It then overlays these so that the frequency with which a given word in a passage is saved causes it to be coloured correspondingly.


In this way, sections of text which were widely deemed important would appear bright red, with those slightly less important coloured orange, yellow etc.

This would form a ‘contour map’ of every bookmarked document. The continuously updating maps might be pasted back into the original documents in order to allow for faster, more effective reading (or better editing). Separate maps could be created for eg interest, importance, limited intelligibility etc.

#878: Gradugrip

Rubber is a magical material. Today’s invention is an attempt to make better use of its properties in a new form of car tyre.

In the top of the image, a car’s wheel is shown consisting of two discs, mounted on telescoping shafts and linked together by a thick rubber skirt. This allows low rolling resistance, which is good for fuel economy when travelling at a uniform speed.


When accelerating or braking, gas is forced rapidly down the gap between the shafts so as to inflate the rubber skirt into a cylinder, thus allowing much better contact with the road surface.

This obviously allows each wheel to experience a continuously variable degree of grip.

#877: Bend-attend

It seems that people pay particular attention to certain movements (it’s recently been suggested that Autists develop a preference for coordinated movement and sound, for example).

Simple linear movement is easy to predict and so our eyes automatically jump to their best estimate of where it will end up. More complex motion requires us to pay a great deal more attention to it.


When there are both simple and complex motions in a scene, eg when driving, we will therefore tend to completely miss certain curvilinear movements -this is probably a cause of those accidents in which people say “I didn’t see him until it was too late…He came out of nowhere”.

Today’s invention is an image processing algorithm which undertakes a realtime analysis on the restricted visual field into which a vehicle is about to move (with emphasis on the margins -from which objects will tend to emerge). It applies directional (Sobel-esque) filters and, when a new curvilinear motion is detected, it issues a “psst”-type warning to the driver.

#876: Troutboard

Remora or sucker fish usually attach themselves to the bodies of larger, seagoing creatures in tropical waters. They have also been known to cling to small boats.

Today’s invention involves massively scaling-up this behaviour.


Given that the fish are highly streamlined, the approach is to arrange that they attach themselves, in large numbers, to the hull of a ship travelling in warm seas. This would result in a potentially large improvement in the thrust-to-drag ratio for very large seagoing vessels (since the extra form drag caused by adding a layer of such fish to a big vessel is tiny and yet they do each provide some extra propulsion).

This source of extra drive could be powered simply by providing a stream of waste food particles via hoses hanging from the prow. It also has the advantage of reducing the many causes of marine fouling which coat the undersides of ships.

If necessary, the fish could be contained within wire cages attached to the hull, in order to stop them jumping ship and to protect them from predators.

#875: ZhabotINKy

Belousov–Zhabotinsky reactions are examples of chemical clocks. Specifically, by mixing two liquid compounds, a solution forms which changes colour every few seconds and which can be made to persist for several hours.

Today’s invention makes use of this phenomenon for the purpose of providing printed animations.


An inkjet printer is modified to dispense dots of the required chemical reagents (these can have their concentrations automatically altered in order to create different colour-change effects in the final document).

A page can then be printed in which regions switch colours periodically and thus enhance advertising material, storytelling or emergency instructions, by providing on-paper animation.

#874: Orbitubes

Debris in space is threatening a lot of valuable missions and endangering lives.

Today’s invention is intended as a possible contribution to cleaning up the mess before it gets bad enough to cause a communications blackout or a fatal accident.


A number of long metal tubes is placed in orbit. They would be of different diameters and with one end closed. These would be repositioned radially, using traditional thrusters, but always aligned circumferentially so as to admit small items of debris into the leading, open end. A detection system would be carried which could spot and avoid oncoming items bigger than a certain fraction of the tube bore.

Smaller crumbs would be involved in a series of glancing collisions with the interior wall of a tube, causing their relative motion to decrease and heating the tube by this frictional contact (but without damaging or deflecting the tube significantly).

The heat generated would be used to power the thruster and imaging system. The tubes would gradually harvest the fragments they came across at each radius. Eventually, each tube would be effectively full and forced to fall from orbit, incinerating itself and its contents completely on re-entry.

#873: Motormouse

Today’s invention is a computer mouse which rides on a pair of wheels, which is free to rotate about a vertical axis. The wheels are powered in such a way that when the cursor is placed on certain graphical elements on the screen, the mouse can be physically driven (across the desktop) as the cursor moves towards the next item that needs attention on the screen.

This system can be used as a training device to help someone learn a specified sequence of repeated screen interactions, for example.


#872: Wiperwindow

It’s always interesting when a great idea gets stretched to the limits of applicability.

One such example is that of windscreen wipers. I was travelling in a bus the other day in which the wipers are over a metre in length. During heavy rain, these need to be flicked back and forth at a speed which is very much faster than is mechanically comfortable for them or effective.


Today’s invention is windscreen wipers for large screens. These move with non-uniform speed, wiping the central region, through which the driver looks most, for a large fraction of the time -only occasionally flicking over the distant corners of the driver’s field of view.

They might even repeatedly execute backwards and forwards oscillation over a central section of the window. This would, of course, require additional coordination between meshing pairs of wipers.

#871: AdReady

Ad blocking software is simply great, but I suspect that many of the good, free things available via the Internet will just disappear if the advertising revenues from online ‘eyeballs’ dry up.

The problem with attending to adverts, however creative and targeted (most aren’t either), is that they get in the way of one’s current tasks.


Today’s invention is therefore a browser plug-in which collects all the information about those online adverts which have been blocked and offers them to the user as a concentrated ad-break…perhaps a couple of times a day, or when the browser is being closed.

These would be shown in the order of being blocked and one screen at a time, so that no scrolling ‘below the crease’ would be required. Extra incentives for viewing/clicking these might be offered (since they would otherwise just be deleted and remain ignored).

A user/viewer might be required to click certain buttons on the ad. page to indicate that they had sat through this display.