eXpresser v1-2819a

The latest version of eXpresser is now released for further testing (download

This release comes configured to start with a familiarisation task that requires grouping.

This version addresses several of the bugs of the previous release (see expresser-v1-2775a post). In addition:

  • It shows the potential colour of the tiles in the ‘General World’  to avoid confusions with the choice of colour for the rule.
  • It shows building blocks of 1 tile in 16X16 rather than the old 32X32, to support the notion that tiles are what  is repeated.
  • It allows overlaps of the same colour to be shown either as darker shades or as crosses (see configuration options)

Known (important) issues

  • We are working on being able to name numbers while in the expression area (Issue 564). So far numbers can only be named while they are in a property list or on the canvas

eXpresser v1-2690

A new release is available (download It includes several bug fixes in the light of the 5th Teacher Advisory Meeting.

Comments welcome.

eXpresser v1-2385

Exciting new release (download that includes an implementation of tiles with negative colours. Turn these tiles into a pattern and add them on top of any overlaps you have. The overlaps are ‘erased‘ !

To colour your patterns in the parallel world, you need to subtract the number of tiles of a negative coloured pattern from the total  number of positively colour tiles. Confusing ? It may be, but the functionality provides an opportunity for interesting discussions with students.

What do you think ?

This version also replaces completely the editing of expressions with the menu-driven editing.

eXpresser v1-2305a

A new version of the system was released for testing with students here at LKL (download

This version employs the metaphor of locked/unlocked numbers for representing specific vs general numbers. That is, unlocking turns the number essentially to a general number. It lets you change its value but it also lets the system change its value in the  “General World“. The animation then in the parallel world is the way to evaluate your construction.


Note: This version also includes a prototype implemention of the help request mechanism through drop-down menus that we envisage students will use to ask help from the system. At the moment it is used for wizard-of-Oz studies (so don’t expect any help, the wizard is away ;-))

eXpresser v1-2044a

Release 1-2044a is now available. It includes major UI changes from previous versions. In particular most actions are now performed through context-aware menus. In addition, student’s world (left) is perceived as the area where students specify the pattern for the computer to animate in the parallel world (right). It is painted appropriately after they have defined the total units per colour that are needed (bottom right area).