eXpresser milestone release

After several iterations, user feedback and internal releases, the latest milestone release is v1-3614b (you can download the zip file here

This is a release immediately after the 6th Practioners’ Advisory Meeting. We are now working on improving this based on user feedback, while thinking about v2 of eXpresser.

This version includes

  • an improved undo for every change in the model;
  • an updated configuration of the textual phrases used by the software, based on feedback from teachers and other stakeholders;
  • a prototype of the Activity Document area where the model to be built and the tasks to complete the activity are shown to students:
    • 1 Tutorial (to accompany the tutorials in How to Use MiGen)
    • 4 activities (Introduction, Train Track, Footpath and Garden)
  • a mockup of eCollaborator with two models from real students about to discuss the equivalence of their rules;
  • a blank Activity Document (My Document) that students can use to discuss about their patterns and rules.

Known issues

  • Dragging from “My World” to the Activity Document and vice versa is sometimes buggy
  • Undo doesn’t take into account actions on the canvas

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 v1-2775a

After several iterations and user feedback, the latest version of expresser is released (download

This version includes

  • Undo for deleted patterns.
    • we are working on undo for expressions
  • Feedback (highlighting) for making clear which property list belongs to which pattern.
  • Improved naming of variables
    • i.e. “Give name” has to be selected first in order to give a name
      (what do you think of the phrase “Give name” ?)
    • After that naming is compulsory and it has to be unique in this session of expresser
      (perhaps it should be unique across all users in a networked activity?)
    • Note that locked numbers -i.e. constants- can be named as well
      (what do you think about that?)
  • ‘mirroring’ of user actions from “My world” to “General world
    • e.g. property lists open in both worlds
    • we are working on mirroring actions on expressions on canvas
      (will also make more clear the change of the value of the unlocked number with the general one when dragged in the expression)
  • Prototype of integrated task description
    (click the Task button near the Play button)

    • Treat it as an object to think with, it needs improvement so your feedback will be valuable.
    • e.g. we are working on being able to show below the pattern a variable changing values while the pattern is animated

Note: This version is configured for a classroom study and therefore doesn’t make available tiles of negative colours. This will be introduced in later sessions (if you want the default configuration use the Configure button when the system starts).

Known issues

  • Names of variables should be mirrored on “General world” (Issue 548)
  • Dragging an expression from “My world” appears behind the “General world
    (this will be resolved when mirroring of expressions is implemented)
  • Closing property lists in “My world” is not mirrored in “General world” (Issue 543)
  • Opened property lists in the “General world” appear in the task description (Issue 553)
  • Of course there are no other bugs 😉

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 v1-2121a

The latest version of expresser was released today (download

After several cycles of improvements and testing with students this version, apart from several bug fixes, demonstrates:

  • Improved tile creation (tiles are dragged from the toolbar and placed on canvas)
  • Revamped property list to make more apparent:
    • repetition of the base shape
    • shapshot as button to open property list
  • Expression for construction
    • see the properties of the base shape of patterns of group of tiles