Colloscope

The weekly oral exam rota (“khôlles”) of French preparatory classes (CPGE): student groups rotate automatically between teachers, week after week, with no duplicates and no group left out. It works just as well for any small-group tutorial or supervision rota. Free, no sign-up; everything stays in your browser.

1 Calendar

First week

Year of the first week

Last week

Year of the last week

Number of student groups

Weeks without orals

Holidays, mock exams…: hatched weeks that do not count in the rotation. Ranges allowed: “52-1”.

Number oral weeks 1, 2, 3… (instead of calendar week numbers) Use A / B weeks

2 Subjects

Tick the subjects and set how often groups go: number of weeks for all groups to have one oral (1 = every week, 2 = every other week…).

3 Teachers and time slots

Colloscope

The grid updates as you type. The number is the student group; “—” is a free slot.

Colloscope title

Several classes, mixed groups, one-by-one orals at fixed times or students unavailable on some slots? Use the multi-class colloscope.

What is a colloscope?

In French classes préparatoires (CPGE), the two-year courses that prepare for the competitive entrance exams of the grandes écoles, students take weekly oral examinations called colles or khôlles: a group of two or three students works on problems at the board for an hour with a teacher (the colleur). The colloscope is the timetable that tells each group when, where and with whom. The same tool fits any rota where small groups rotate between tutors: Oxbridge-style tutorials or supervisions, lab groups, language conversation classes…

How does it work?

Calendar: first and last ISO weeks (September to June, over two calendar years, 53-week years included), number of groups, weeks without orals.
Subjects: tick them and set how often each one comes round. Add a subject that is not in the list if needed.
Teachers: one line per teacher, with subject, room, days and time slots. Separate several slots on the same day with ; (5pm-6pm; 6pm-7pm); a room for one slot only is written 6pm-7pm @F008. With A / B weeks, a teacher can come every other week only. Panels and teacher cards fold up (▾) to save space.

Rotation rules

Within a subject, all teachers' slots are pooled. During one rotation (the subject's period), each group has exactly one oral.
From one rotation to the next, slots are shifted by one: groups change teacher.
Each subject needs at least as many slots per rotation as there are groups (e.g. 16 slots a week for 16 groups with weekly orals, 8 for fortnightly orals). If some are missing, a message says how many: usually a slot left out. Meanwhile the rotation is spread over more weeks.
Weeks without orals do not count; slots reserved for A or B weeks only count in those weeks.
Each week, groups are placed on the slots of all subjects at once: a group never has two overlapping orals, and preferably goes to the teacher it has seen least. A slot without an end time (5:15pm) counts as one hour. If slots are too concentrated to avoid every overlap, the cells concerned turn red.

Save and share

The colloscope is saved automatically in this browser. Save creates a .json file to keep or send to a colleague, who opens it with Open. Save the team keeps only the teachers, their subjects and slots: next year, set the calendar, then open that file. Print / PDF prints the table only, in landscape, with its title; LaTeX gives the source code of the table.

What is a colloscope?

In French preparatory classes (CPGE), students sit weekly oral tests called colles: small groups of three spend an hour at the board with a teacher (the colleur). The colloscope is the timetable showing which group goes to which teacher each week. This tool builds it automatically.

Example: a class with 15 groups

Calendar: weeks 38 to 21 (mid-September to late May), 15 groups, weeks without colles for holidays (43–44, 52–1, 8–9, 16–17) and mock exams.
Subjects: maths every week (period 1), physics and English every two weeks (period 2), French and philosophy every three weeks (period 3), for example.
Teachers: for maths, with 15 groups and one colle a week, you need 15 weekly slots of 3 students, shared between several teachers; for fortnightly physics, 8 slots are enough (15 / 2, rounded up).
Result: the grid gives the group number for every slot and week. Each group sees each subject once per period, with no duplicates, rotating across teachers.

Checking and adjusting

Number of slots: a subject with period p needs at least (groups / p) slots a week. The tool flags a shortfall; add a slot or lengthen the period.
A/B weeks: useful when a teacher only comes every other week. Choose whether holidays break the alternation.
Numbering: show colle weeks as 1, 2, 3… for students, or calendar week numbers for the office.

Sharing the timetable

Print / PDF for the classroom wall, A4 landscape.
LaTeX: a file to compile with pdfLaTeX, the table scaled to page width, for a start-of-year booklet.
Save (.json) to come back to it, and save the team to reuse teachers and slots next year.

Good practice

Make groups of 3 students of mixed ability and keep them for at least a term to follow their progress.
Avoid two colles on the same evening for a group: spread a week's slots over different days.
Keep a buffer week before holidays to make up cancelled colles.

If your colles mix several classes, include individual timed slots or students unavailable at certain times, use the multi-class colloscope.

Guide written and checked by Erwan Hautot · updated 29 October 2026.